Please Help!! Internal or external??

Kind of a stupid question on my part - I assume you did not have the internals balanced ? If you did, it has to be internally balanced then, since you did not provide a balancer for this purpose to the engine shop. They would only be able to balance it neutral. Then a neutral flex plate and vib dampner will be needed.

Do you have the old stuff from when the motor was dis-assembled ? that would tell you as well. The externally balanced dampers will have a bell crank shaped weight on the front of them and be marked as such for external balance, the neutrals have no offset weights and look symetrical.

There is no way I no of to determine what the crank is - without examining it as described above, pull the pan and look for: thin sharp parting line = cast crank, thick 3/8" or so parting line = forged crank.

Another thought - do you have the part number or casting number of the crank ? You may be able to find out that way.