Mentioned this in chat, but I'll bring it up here and cross post between tymcneer and the PPS threads:
How about instead of laser engraving, just etching notches in the OD, similar to what AGD does on the Level 10 carriers? e.g. 1 notch for .675, 2 notches for .680, 3 notches for .685, 4 notches for .690, or whathaveyou?
Since I'm assuming these are hanging out on a lathe during fabrication anyway, that would eliminate the need for another operation or bringing the inserts to a different tool / engraving shop for identification.