I order 2 extra mags for my 527 in .223 a few years ago from CZ. Received them in the mail. When I opened them the follower was stamped .204, but the package said .223. Returned them to CZ. They were supposed to get back to me when they had .223 mags. Never did. They were indeed .204 mags.
I stopped by the friendly LGS in Wichita, and I noticed that they have the CZ 527 mags, 7.62x39 up on the wall. If the OP is still looking for them, give them a call 316-686-7264.