Engine Serial Number Decode..?

I've searched up and down for a decoder or list of engine serial numbers and no luck. I had to pick up another motor for my '84 vf500f, and the guy told me it was out of an '86. However after rigorous searching, the only site I found confused me. The serial number is PC12E-200006268 or something to that effect(not sure if the 6268 is exactly what it is off hand). The site said that a PC12E-20000001 is an '84, PC12E-21000001 an '85, and PC12E-22000001 an '86. Again, these may not be exact but I'm guessing that the "200"'s match to what they say is an '84. I just want to be sure to get the right plugs and everything for the right motor. Any info?