Prior to the paint job, that could quite possibly be the ugliest SNES I have ever seen. It looks like it was stored in the bottom of an outhouse. I would have kept a dust cover on it non-stop just so I wouldn't have to look at it.
Nicely painted. I'd paint the rest as well, just to hide the last little bits. With them unpainted, the memory of the "ugh" factor will still haunt you every time your eyes fall on the unpainted bits.