My 2 cents on this question: Leave it alone. The milling into the table is relatively shallow and not of a large enough area to affect about 99% of the jobs you are likely to do on that Bridgeport. The machine is hardly "cherry" nor is it a toolroom machine. Vises, rotary tables, indexers and similar will span the damaged areas, or simply can be located on either side of them. Larger jobs to be clamped directly to the table are usually setup on 1-2-3 blocks, matched heavy parallels, or on a variety of other things such as hardwood (for rough castings), shims (for oddly shaped worked), planer jacks (aka jack screws) and anything else that works to support a job so it can be clamped to the table. On some really oddly shaped work, a few points are supported on shop-made fixturing, and it becomes a matter of indicating a reference surface and/or "picking up a center location" on the work. In those kinds of jobs, the condition of the table becomes irrelevant.
I remachined a Norton motorcycle crankcase half a couple of winters back. It had no real good surfaces to lay on the table of the mill to clamp down. It was a case of setting up on simple shop-made fixturing (keep plenty of scrap steel and aluminum at hand for jobs like these, and being handy with welding does not hurt). A main bearing counterbore and crankshaft seal counterbore had been damaged. These were bored oversized, and a new "pad" for the seal counterbore was TIG welded to the crankcase. The maain bearing counterbore was built up with TIG welding. I had to re-establish centerline of the crankshaft in the crankcase half, and get it squared with the split joint of the crankcase. There was no clamping anything directly to the table, but supporting it on some fixturing I'd made, then using shim stock between the base of the fixturing and the table to bring the split joint surface into square with the spindle of the mill.
Another exercise which can lead to temporary insanity, which I call "chasing my tail", is tramming the head of the mill so it is dead square to the table in two directions. I use two "match lapped" parallels which are 1" x 2" x 12" laid across the table to indicate off of when I tram the head. I use a home-made "tramming bar" to hold a dial indicator. The parallels span the width of the table, so even if there were localized damage, those parallels catch the plateaus or high spots.
I tram the head of my Bridgeport anytime I shift the ram position, and before finer jobs such as boring or work calling for close tolerances. I "kiss off" the table with an Arkansas Hard oil stone (a white stone that is so smooth you'd swear it would not remove any metal). This gets rid of any small burrs. Tramming the head of a mill is good exercise in use of dial indicators. Invariably, you find that last thousandth does not quite want to be adjusted out. You give the adjustment to the angle of the head "one little tweak" and discover the indicator is now reading somewhere out in left field. After a few times, tramming the head gets to be more routine. It's good practice to check the head of a Bridgeport if you have adjusted position of the turret (base of the ram) or the ram itself, or if you are returning the head to square after having done a job with it at an angle.
You will be quite surprised at how little, if any, difference the damage to the table makes when you get into using your Bridgeport. I'd suggest taking an India Medium Hard small oil stone and lightly stoning off the table. Using a circular motion and keeping the table wet with something like penetrating oil or kerosene, the stone is worked over the whole table, trying to be as uniform as possible. The object is not to remove any significant metal from the table, but to take down any burrs or "dings" (raised metal created when something harder was dropped against the table or driven into it). Use the heel of your hand to lightly run over the table to feel for any burrs. Once you have stone off the table, Tramming-in the head is a good idea. This will get you setup for most milling and drilling operations. Before you mount a vise on the table, stone off the bottom of it as well. If you store a vise or other tooling off the mill, it is a good idea to put a soft wood board (pine) between the bottom of the vise and the floor or shelf it is going to be stored upon. A steel shelf or concrete shop floor is likely to raise burrs or put some dings into the bottom of a cast iron vise or rotary table or similar.
I keep several oil stones handy in my "roll away" machinist chest. These have various shapes, and most are "India Medium Hard", with a few small "Arkansas Hard" stones as well. Good work habits will go a whole lot further in producing good work than a pretty table with no visible damage, IMHO.
Plainly, while a table free from visible damage is pleasing to the eye and may make a person feel good, it is not a necessity for doing fine work.