Italian Registration Numbers

Hi

I’m trying to understand the Italian system of registration numbers. This is for a 1937 bike. I know that the first two letters represent the area code. In my case SI for Siena. I would have thought that there would be 4 numbers after that, being the progressive number, but I have 5.

So the format is SI * 1 NNNN

Could it be that the “1” is a region of Siena? Or did they really sell 15,000 vehicles in 1937? If it helps the rear plate is in this format:

SI * 1
NNNN

It’s white with blue lettering.

Any help appreciated.

Cheers
Niall

Have you seen this?

Vehicle registration plates of Italy - Wikipedia

“From 1927 to 1932, Motorcycles used to have white digits on a black background and the provincial code was after the digits on the second line, in 1932 (to 1985) the motorcycle plates changed to a white background with blue digits, the provincial code was moved before the digits and like cars, Motorcycles used the Garamond font until 1951.”

Yes saw that thanks. Very useful.

I’m being told that the number 1 after the Siena code denotes the number of Moto Guzzis registered in that year. Followed by the progressive number.
I’ll try Facebook for more.

Cheers
Niall

Very interesting!