Band gets noticed... then what?

My friends have made a band. Im not in it as i cant play an instrument, but i help with the lyrics, i design album and singles artwork, i also edit some songs using digital software on my pc (none of them is as computer literate as i am). im considered part of the band, but not exactly. my question is, if they get noticed for anything theyve created (songs) and ive helped create, do i have any claim on it (we dont have contracts within ourselves or anything). cuz if they get noticed then im not a really important part of the group, so will they (or can they) just drop me? I mean, without giving me anything?