Had a similar situation with my 34 Plymouth. Could not find a VIN on the car at the time of registration, so PA issued a new registration and VIN. A little while later found the original VIN plate, but not where it should have been. Although it would have nice to correct the title I decided not to. Another problem was that the title I got from the previous owner which had recorded in Ohio from a Louisiana title used a VIN on the title that did not match the VIN type of that model year, so PA rejected both the Ohio title and the Louisiana title. Seemed that when the car was built and registered in Louisiana, the builder used the S/N from the original 6 cyl engine and not the frame. PA would not accept this number.

Strange things happen to original VINs when cars get built. In many cases they are removed, some of which are lost, and new numbers created. If the new creation doesn't match the type of code used for that type of car, many states might reject. Obviously, La and Ohio did not in my case.

If you were given a new title and VIN for your car from your state, you might want to stay with that one cause that is how the car is registered. If you have not gotten a new VIN plate, then it is up to you which way you choose to go. In any case, expect delays and plenty of scrutiny.