I've been in a couple of different countries that have used the 52 religiously and I've yet to see a select-fire version...even modified to that. However, I have been up close and personal with the silencer equipped version and the actual rifle (ultra-uber-rare) designed/modified to shoot the 7.62x25 cartridge. That rifle is a heavily modified CZ-SHE rifle and produces very ugly results with Bulgarian High Velocity steel core ammo.
Of course, I'm not surprised that I ran into both of those. My team discovered a fighting position that had AK magazines that were made of hardened medical tape, a spring, and a follower.