What is the difference between the "DETONICS .45 A.C.P." and the "DETONICS .45 AUTO" stamped magazines? The only differences I can see are in the shape of the spring (where it contacts the follower) and the cutaway at the top-back of the body ("tube"), which is wider and shallower on the "AUTO" model. Are they both official Detonics? They appear similar in build quality. Which, if either, is more desireable?

Thanks,
Cliff