JayFramer, the YOM is stamped on the right side of the receiver and barrel at the stock.
In the early years buyers complained of bolt clearance issues and new scope with large adjustment rings. My photo is an older Weaver K2.5 post reticle scope on my Lux .22 Hornet. Twenty years ago CZ and Warne (IIRC) were the only supplier of rings for the 527 series. There are now other companies making the rings and pictany rails are available to fit the receiver dovetails.
CZ is ridiculously proud of their magazines. I found J&G Sales in AZ to have better prices.
A man named Shaun Frame in Ohio designed and made Delrin bore guides for the CZ 527. He graciously gave this to a shooting supply company so it could be reproduced and sold at a reasonable price. Check Brownells and Midway USA.
Of the ten CZ 527’s I have owned, six are still in the family. None of them ever shot to the same POA if they were sighted in using the single set trigger then fired using the trigger in normal mode. Experiment with yours.
Enjoy it.
Interesting! I'll probably only use the "normal" trigger mode.