Thanks guys.
Not sure if it's a DeKerf built, but my understanding is that he did a lot of the tig welded Thunderbolts. So it's likely, or at least possible. This one was built in late 1992 though, so I'm not sure if he was still contracted to Rocky at that point? I think RockiMTN/Frank has a detailed thread on his Thunderbolt---I'll read through it and see if I learn anything helpful for this one.
On pins and needles to receive it. Hopefully this time next week?