I feel that the Mk 1 and 2's with the power adjuster, two stage hammer and adjustable trigger are the best of the early Crosman CO2 pistols. Good luck with the power adjuster. Crosman didn't use any kind of anti-seize lubricant on the adjusting screw; as a result the adjusting feature on all 4 of my early Mk's is frozen in place. I tried to force one and it broke.
Nice guns, you're going to love it. I have a Mac1 ldc on mine, two thumbs up!