Ring H-D Customer Service in the US. Try 0011 1 414 343 4056. Tell them your frame VIN and LEFT crankcase production number. NB: your frame VIN and engine VIN should match each other. Also, your R-H crankcase production number is probably inside the gear compartment and not visible with the engine assembled.
The VIN and crankcase production number may be on file at H-D and if so the factory may send you a letter of confirmation. It's possible you may be told the date of assembly, the colour, whether it had footshift or handshift and maybe even the name of the dealer it was sent to.
Your bike may also have other ID the factory could confirm. Stamped on top of the padlock plate on the lower triple clamp you may find an additional original component identifying number--for example, AB 1234. Similar ID may also be stamped on the front of the gearbox on the R-H side just below where the lid attaches--for example, N 1234.
The two sets of ID numbers probably won't match each other but that's okay because they're not meant to.
Eric