Music theory question

[hanalei.allen]

FAIR WARNING: it's ok to laugh. This is a very uninformed ("stupid") question from a multi-instrumentalist that started on the drums and has a rather profoundly suspect knowledge of music theory

MY QUESTION:
If I grab tablature (which often has no key signature) and learn to play the verse of somebody else's song on my bass and guitar and then notice the 99% of the notes I play are exclusively ABCDEFG (no sharps or flats)can I both
A) correctly assume this part of the song is in the key of C
B) grab the keyboard, add in a key solo that only uses rapidly played ABCDEFG (no sherps/flats) 16th and 32nd notes, them assume it'll likely NOT sound discordant because both my solo and the background music are in the same key?

Thanks ahead of time!
Sincerely,

Kindergarten-level music theory dude

 

[CowboyNQ]

Short answers:

A) Not necessarily
B) Not necessarily

Not trying to be a smartass, but those questions don't really have "yes/no" answers. Assuming this is a real-life example, if you can share the tabs for the chords and melody there might be someone on here who plays guitar who might be able to give you a more useful answer when they know what they're dealing with.