Peeped at my bores again and really got in there to look around. Didn't find any corn this time, think i got all of that out. Anyway, I think the thing was definitely done up back in the 80s, rings, gaskets, bearings, etc. There is almost no ridge at all. It comes off with a vigorous scrubbing with a red scotch brite. It's very rudimentary and probably not even close to being accurate, but I took my .002 feeler gauge, stuck it in the bore and ran it upto the ridge and ran my fingernail over the ridge and the gauge. My finger would catch on the gauge, not the ridge. So I think it's safe to assume the ridge is slightly less than .002. I'll measure it better when I actually get the funds to tear it down completely, but the bores look pretty damn good, the cross hatching is terrible, looks like the rings were spinning too fast. Either way, i think it'll hone up fine and take new rings.