Personally I have spent most of my vacation, digging further into the interesting world of VIN #'s.
I thought I knew a lot, but I am happy to find that there is an endless source of knowledge to go through.
California Highway Patrol Released a booklet in 1970 for motorcycle buyers, to ensure awareness of alterations in realtion to stolen motorcycles and their VIN #'s.
That is a good place to start.
Click on the Front page - or here - to load the entire booklet - it might take a few moments, but is worth the wait.
The link is from Chris Haynes' Website Vintage American Motorcycles - a great ressource for historically interesting pictures and documents. -Chris is expert in VIN #'s to say the least.