Since they are not registered, there is no way to answer your question. In the US, MOST guns are not registered- there is no law requiring that guns be registered. It is a popular misconception that there IS such a requirement, but there is none on a Federal level.
No. Pennsylvania doesn't have gun registration.
IIRC, they were all legal.
No.
No - that is theft, all the same. Theft of a firearm is a felony.
Almost all guns are manufactured with serial numbers and are traceable, provided they are registered when purchased or transferred to a new owner.
Like most of the US, there is no registration of guns in Texas.
No- see link below.
No, but gun owners do.
You cant'.
None of my guns are registered in Ohio, but I don't live or visit there, so there is no penalty at all.
Many places don't require it.