If your spindle lubrication system is working correctly, the spindle journals never touch these surfaces in operation. Heavier scoring does result in lower off-axis loads before the spindle breaks through the hydrodynamic bearing film, but in a home shop on Heavy 10 I don't think you should lose sleep over it.
Here's a video clip of my 16" pumping oil via capillary oilers through the bronze sleeves. It's not segmented cast iron like yours, but relies on the same physics and the same oil felt system. I have read that the longitudinal slots in the cast iron bearing headstocks were cut to reduce oil cavitation, but I don't have enough info to back that up.
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It should run fine for many more years, just make sure the felts are clean and the reservoirs are topped up.