Hey, Ashley,
Welcome to our little nut house! And by the way, despite Gene's protestations to the contrary, he's got way too many air guns to be a baby anymore! But I digress.
1. Yes, the NRA 1000 is just a special edition of the S1K.
2. Backwards pellet!? Other than possibly getting jammed, it shouldn't do any actual damage. In fact, I just recently read a post about someone intentionally shooting Beeman Crow Magnum pellets backwards. Supposed to increase the expansion, I guess. Regardless, if the pellet is stuck in the barrel, just use a cleaning rod or something similar to tap it back out.
3. Most of the mounts out there have a reversable clamp jaw, so they will work on both 11 mm and 3/8" dovetails. Could that be the case with yours? And no, you definitely don't want to force the rear mount up with the recoil stop pin. That said, I'm becoming more and more convinced that ALL air guns can benefit from adjustable mounts. I remounted my Leapers scope on my CFX, using Accushot 1 pc. high mount. I optically centered the scope first, and it took more than 2 1/2 full TURNS of the elevation knob, not clicks, to get it on target. I also mounted a scope on my RWS 350 using a Beeman adjustable mount. Again starting out with the scope optically centered, I was on target in about 5 clicks of W/E. Everyone talks about the RWS rifles being droopers, but from what I'm seeing, it looks like all springers have it. Safe to say I'm sold on the Beeman adjustables, although I may have to go with B-Square for my CFX and Leapers scope. No 30 mm high adj. available from Beeman. Accushot are good mounts, but not adjustable. BKL's look rock solid, but they have limitations. Look at the Product Reviews, Gene and I both did reviews on the BKL mounts.
4. I already covered above :-). But I will add that if you decide to send your rifle to Bob (CDT) you won't regret. You won't recognize it when it gets back, but you won't regret it. It may look the same, but it sure won't feel the same. Hope this is some help, and good luck.
Dave