The numbers are stamped into the block where the oil pan flange bolts up... toward the back on the driver's side. There's no code, those are the bearing sizes as they were installed at the factory. If you follow the procedure in the TSRM you can get MUCH better clearances then by just using the same size that fit the crank 20+ years ago...
It's kind of foolish to not replace all the bearings while you're in there, IMO. Damage or not the bearings and crank both wear and continually lose material... you're already doing well over half the work.
Did you do a leak down test to see how the rings are holding up?
Shame on your "mechanic buddy" for not giving you crap for trying to take the lazy route. :P
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