Hi there I have a 1970 Boler and have noticed some subtle differences to the newer models even when compared to 1972 ect...I know they started in 1968 and only made a hundred or so before the 1970 year when they reached 500 or so. My VIN is actually 283.
From what I hear mine was one of the first 500 or so made?
Differences I have noticed compared to newer ones in the 70's:
1. my tail lights sit flush (not recessed)
2. floor is wood - not fiberglass (the under side is coveredd in a thin film of fiber galss to protect it.
3. no window above stove
4. Rear bumper is tubular (not square tuing) and there is no mount for the spare tire.
5. no side reflectors/lights
6. odd wiring plug on side for 120 volts.
7. The water tank filler is ust a chrome box with a little chrome door, no hose hook up here.
any other changes after 70 that I am missing?
Here are the pics of my work in progress....
http://www.cardomain.com/ride/2307057/1