Chris,
I would not be overly concerned about the whine in the bearings, especially if the ambient temperature, and hence the machine temperature, was much below 55 degrees. I have heard whining noises from many of my motors and spindles (ball-bearing type) machines when winter comes on (shop is currently unheated).
I would suggest putting an indicator to the spindle, and checking for play and run-out to be sure. Too, due to age, the bearings will very likely need greased. Although I've never greased the bearings in my Fray, ever, and they are likely of the "sealed" variety, it is good practice to pop open the shields and re-lubricate such old bearings.
A couple of items to note about the Fray mill and attachments. First, the Fray milling machine head is the exact same, bolt-for-bolt, as the Fray milling attachment made for horizontal millers. All the company did, was to add a column and table to their head to make a light duty milling machine. Regarding the head, the casting appears rigid enough, and the overall assembly is of decent quality. The problem areas are with the motor mount plate, and the belt pulleys.
First the plate. While of only 1/2 hp or so, the motor carries substantial weight, and applies significant stress to the mounting plate. Quite frankly, the plate is not up to the challenge, and has a much too thin cross section. The plate on my Fray head broke on us a couple of times, and had to have a strengthening "sub-plate" screwed to the top of the original to beef it up.
The belt pulleys are another matter. Cast of some rot-gut pot metal, they have occasionally shed chunks of metal over the years such that only about half of the pulley steps are now usable (this is on the spindle pulley). The motor pulley, while not suffering from the same effect as much, does seem to be afflicted with a type of delamination, where there the beginnings of separation between pulley steps. Also, the pulleys have deformed, and no longer run true.
I don't know if Fray used the same pulleys and plate in all their mills, so this one may not have these problems. That said, be aware that at least some of the mills used these defective components, and that they may need corrective action down the road. Furthermore, while sounding bad, neither the pulley nor the plate problems are very difficult to solve, and are quite straight-forward repairs if need be done. In my opinion, given the right price, the mill should still be worth purchasing.
J.D.