hi there i bought a drz400 for a bush basher, I bought it on the belief it was a 2003 starting to think it a really early one ?99 or 00. as the newer ones don't have the allan key bolt in the side of the head ( what's it there for anyway ) How can i tell ,???? frame number ??? anything else that may be a tell tail sings. i've hear people asking about the 10 digit on the frame number? is that correct.