If so can you get them back?

Pete

Personally, No; in limited circumbstances, Yes.

A lot depends on the reason for the prohibition.
(in other words, more details are needed to answer your question with more than just generalities)

There are two issues here: both state and federal law must be satisfied.

As for state issues: States differ, ie: see Washington state as an example:

The only difinitive answer re: removal of a state's prohibition is to check with your state's attorney general.

As for federal law, see 18 USC 922 for persons prohibited to own firearms under federal law.  

The particular federal prohibition, if any, will lead you the next steps that may be available.

Cheers, Otto

edited because I can't spel

Quoted: If so can you get them back? Pete

Most do when they ETS, but that's another story entirely.

In your case, go back in time to before GWB was elected.  Make large donation to Dems.  Receive pardon.