I don't have a pic, and can't post a pic, I have both, and they both work, in ,my MK III, 22/45, one has a "slot" near the top, and the other doesn't .....
They are real easy to tell apart. On the left side of the mag about 1/4 of the way down on the MK III mags is a small cut out and a slight bump. This is for the lawyer crap(mag disconnect)
The gun on the left is a Ruger Mark II. The one on the left is a Ruger 22/25. The mag on the left of the picture is for the 22/45.
The mags will not interchange in these two guns. The Mark II has a smaller mag base and has a rounded edge as you can see in the picture on the left near the top of of the mag well.
The 22/45 has a much larger base.
I don't really know the difference from the Mark II and the Mark III. All I know is they are stupid expensive for what they are (about $20-$25.00).
I don't have any mags for my Mark II but I need to get some soon.
Like Simon6101 said, the MKlll has the retaining or latching bump relieved out about 1/4 of the way down on the left side while the MKll being bottom locked has none. This is easily seen and felt in darkness. Otherwise , they look much the same.