Welcome to the Team Austin!
While the frame is all cleaned up you should verify the VIN stamped on the passenger side rear frame rail (aft of the ten bolt housing with twin upper control arms) to verify it matches the one on your title. If they do not match, now is the time to grind it down, weld it back up, grind it back to flat again, and then restamp the frame with your titles VIN. People swap frames do to impact damage or corrosion but cops think the only reason is it is stolen.
If you are going BBC it would have a partial VIN with an appropriate date code as a well as would a 350 horse 327 SBC. The base 300 or 275 horse didn't get a VIN stamp, nor any of the six cylinder motors.
Probably make getting it licensed to drive on the road easier when the cops get around to checking it out before issuing tags. Stateside if those numbers where on the NCIS list of stolen cars you would loose your recently restored ride without so much of a by your leave...