At the very least it appears that the software in Target's STB7766C (as in "Cow") is almost identical to that in the RCA DTA800B1. Consequently it has the same limitation(s), namely that it has only two aspect ratio options rather than the required minimum of three or more that the STB7766G or STB7766G1 have. RCA should have fixed this long ago. Since the packaging looks identical, I think it's very likely that many people will think they've got a "G" or "G1", when in reality it's a different animal. Fortunately I was able to exchange the box for one of the few remaining "G1" units.
When calling a store to have them hold a box for you I suggest you have the clerk read you the model number on an actual box rather than off of a shelf label.