yz 465 identity?

[mx392]

I've recently purchased a yz 465 that was supposed to be a 1980. The frame and engine #'s are matching and that of an 81. The bike has original plastic, bars, seat cover, etc. But, the tank graphics are 1980(and show their age) and it doesn't have the boost bottle or the intake for it. I didn't check the fork size. Was there a cross over period of bikes being made? Trying to restore and not quite sure which way to go. Any input would be great. Thanks

 

[MOgle80]

the 80 has 3R5 as serial number ...the 81 is 4V4 to start with ....maybe the stock tank got damaged so they changed it , also changed the intake to 1980 items . Just a guess. The forks could measure 39 or 43mm but I can not remember if 1981 had a change over other than right off the bat.