Also, since guns aren't registered down here is there any way for the cops to know for sure that it is her gun?
She reported it stolen.
If they're saying it's the same gun, I'd be willing to trust them on that....
Glocks have these little strings of characters on them, called a "serial number". It lets people identify a particular gun.
so are there any kind of forms they will have her sign to indicate that the gun was stolen and not in her possession from X date - Y date?
The Police report from when it was stolen.
The forms she'll have to sign to pick it up.
One says it was stolen. The other will say it was recovered by the Police and returned to her. That's about as good as it gets.
If that still isn't good enough for her, she can sell it.