I've inherited as much of the functionality as possible from the older firmware, but it appears that the memory layout is quite different. The older firmware uses frequency + offset, whereas the new one uses independent TX and RX frequencies (there's some evidence online that it supports cross-band splits...need to test that). The symptom when using the existing CHIRP support on new radios is that the memory gets blanked out on upload, because there's more memory on the newer units and the layout of individual memories is different.
Bummer, but that justifies having the different class, so that's fine.
I think I have access to an older UV3R, so I may be able to find the model number indication somewhere in memory. Without a few more images from the wild, though, I'd be concerned about hitting the right spot.
Yeah, we have to be able to detect the images properly (the patch won't pass unit tests if not). There is an image in the tree for the older one, if you want to take a look in there. Also, the users mailing list is a good way to grab a bunch of sample images if you're willing to survey them.
Thanks!
--Dan