Well that's inexperience talking. A basic google search reveals an
old blog post from our buddy The Longhorn Engineer. He was at MGC this year so you probably even met him. Anyways, there's definitely two boards in there. From what I remember from portablizing one of these myself, you can remove the NES board and the SNES stuff will still work fine, but the NES board is reliant on the main one.
Older shit like the retro duo isn't exactly an emulator like you'd think. Hardware emulator, maybe. I seem to remember the sound quality not being as good as an OG SNES.
It's a pretty good candidate for a SNES only portable, or maybe a combo one that does both like in the blog post. I have virtually no experience with the NES aside from relocating it's cart slot(something I did for a repair job once ayy) so you'd have to find something else for that. THere may be new options. Worth doing a little more research for sure.