i could see ds's swollen gums half across a room at 13 months when he would open his mouth. even the ped commented on how swollen they were. i started feeling when he would let me and could feel the hard nubs coming through and then i could see them. i would also lay him down and get him giggling and could peak in there at the same time to see.
Re: dumb molar question
If you can't look or feel in her mouth then you'll never be able to tell.
DD will let me rub her gums. I could tell that they were swollen for a few weeks before she finally cut her molars.