Very likely. Hopefully they are all exposed and available. DIY could be anything though.
It WILL be either AWG14
You don't know that; that's what it SHOULD be. And occasionally some 10.
and the receptacle (outlet) WILL be rated
You can't know that. Your'e not there.
If it is a 20 amp outlet it will have
==INto which a 15A will still plug just fine. ==And which does not mean 12 wire, or even a 20A breaker. It could be 14 wire, and I've seen a few
30 Amps where 15's belonged, one right here in my own home when we moved in, in fact, in addition a flooring nail thru an insulation right at the staple point. == And there is no guarantee a 20A or more appliance still has a 20A connector on its cord.Usually; unless it's encountered a run of 14 ga along the way where it needed to be 12. in that case a full draw near popping the breaker (of unkown amperage) can indeed melt and otherwise compromise the insulation.
Never, EVER depend on code to represent what one will find in any home they did not have wired, or wired themselves, and had inspected. Any inspection only speaks for what it WAS, not what it IS. When you buy a home, you're also buying whatever the last owner may have done to/with it. And never take anyone's word for anything; they may just not know any different.
I once even found a 26ga twisted pair solid wire used to provide an extension for the last foot of a run inside a wall for an added outlet where they couldn't pull the wires far enough to reach the new position. They spliced it at the old location, soldered & taped it, then plastered it closed & painted it. They matched the pain perfectly but couldn't be bothered to get the proper wire for the job, or care about codes. Lots of people are similar to them but hopefully not quite that ignorant of reality.
No: I'm not a contractor, lawyer, insurance agent or electrician. Just a diy'er who knows the code & helps people out since being forced into retirement for health reasons. But, like the condition of wiring in any home, I'm nost exposing what I WAS or even which union I was in.
Twayne