Some (all?) Aermacchi H-Ds had frame numbers in the 1960s and some examples I’ve recorded did match the engine number.

H-D Shovelhead frames first received a VIN boss as of late-1969 models although originally it was not stamped and the boss was only in the forging in readiness for 1970. But not all 1970 model Shovel frames were the same. Most had the boss and the VIN was stamped on it but some late-70 model Shovel frames did not have that boss and their VIN was stamped further forward. Also with no boss were some early-71 model Shovel frames and their VIN too was stamped further forward. But apparently the 1971 frames with no boss were all used up while VINs were still in the low-12000 range and H-D went back to the 1971 style we normally find, meaning frames with a VIN boss and the VIN stamped on it.

Something you could ask the authorities about is if a different type of frame ID would be acceptable for registering certain Harleys in Victoria. Shovel frames for 1966–69 had an additional original component identifying number, aka security code, aka anti-theft number, aka supplemental number, stamped on the left side of the steering head. And so did some, but not all, 1970 models even though they had a VIN.

On Panhead frames the additional ID is on 1962–65 models and it’s also possible that some, not all, 1961 models had it as well. The extra ID consists of one letter followed by either three or four numeric characters but they are only about 1/8” tall and may be hard to see especially if the frame has been powdercoated.

A 1968 model Shovel frame could have the letter G, H or J. (The letter I was skipped in this type of frame ID.) But J could also apply to 1969 model frames. Photo below shows H4+++ on a 68 model frame. Let me know if you need more info.

Eric