Vintage Dirt Bike Q & A

Hi, New to forum. I just picked up a '74 Elsinore CR250 and had a question re; the VIN numbers. I know a bit about Hondas but don't know a whole bunch about the Elsinore specifically. I had a '74 back in the early 80's I used as a play bike, but it's long since gone. I was around when they hit the tracks, so I remember their impact and all the hoopla around them! The present Elsinore has a frame # of 10236xx and the engine has a # of 10266xx, almost exactly 3000 digits separation. That seems pretty large to me. I have a CA State OHV validation dated 8/76 that has the same numbers on it, so this frame/engine have been together for a long time. The question is; Do I have an early factory replacement engine, or could this be original install? I've read elsewhere that the last frame # was considerably lower than my high engine #. Also, the OHV validation says the bike was first sold in 6/76, so either it was a real late sale or it came from a state that did'nt require a title and was titled in CA in 6/76. I have heard of some unusual VIN spreads on some documented bikes. Anybody have any thoughts or info on this? Thanks, Rob