Er....
<tries to apply logic>
Let's assume that it (or a derivative) had an aggressive role in WW2. The designation, therefore, might be an uncommon one. To be reused, it can't be a USN designator, although it might be a USN a/c employed by the USAAF. Since the Pursuit designation went, it can't be a straightforward 'P-something'.
So...
Er.....
Help!