There's a very old thread in the archives from around 2000 where a member discusses having a PCR that had "MOD.PCR" on the right side of the slide ahead of the ejection port. I've never seen one in this country that actually had PCR on the left side of the slide and they've all been 75D COMPACT roll marked. Guns made for the overseas markets can have different roll marks too. CZ has been known to do interesting and confusing things with roll marks at time.