Quite honestly though, Ripper, unless you're a real stickler for a 100% accurate Spas 12 cage, so long as it's the right overall dimensions I think it's fine. The only people who might notice are mostly on this board, the general public could care less. Kind of like the 8 vs. 10 hole barrel vent issue. Having 7 holes on your Spas 12 cage rather than 8 is much less of an aesthetic issue when compared to a Thompson with the bolt on the side vs. on top of the receiver.
So long as you're happy with it, that's all that matters. And if you're really that unhappy with it there's always other projects that the parts can be utilized for. Like me with my recent project.
-Alex
"The M41-A. When you absolutely, positively have to kill every mofo in the room. Accept no substitutes."