Just a standard Mk-II, no mods except rubber molded grips (still have the walnut grips, though). Doesn't get shot much because it is such a PITA to reassemble. Normally, cleaning after shooting is a relaxing event: some decent oldies playing and my favorite adult beverage nearby. Always clean right after shooting.
I have other .22 pistols (Bersa Thunder, SR-22, etc.) that are considerably easier to reassemble, so they are my preferred .22 pistols for plinking. Downloaded a step-by-step disassembly/re-assembly guide, and refer to it every time I venture into shooting/cleaning my Mk-II. It is still frustrating...I can disassemble, clean, and reassemble the the others faster than I can re-read and follow the detailed instructions for the Mk-II.
It's a crying shame, because that Mk-II is an incredibly wonderful shooter. Got it in 1983 and probably haven't put more than 500 rounds through it because of that. Wife loves it, but she's got her SR-22 now, so it sits as an emergency back-up in the barn area, should I encounter a copperhead or a rabbit armed with a Holy Hand Grenade.