Tailgate for a 64 or a 63 c-10 half ton

[krashkhris]

Are the tailgate and other body parts hard to come buy for the 63-64's?
Also how can I tell the diffrence between a 63 and a 64 I've seen some pictures of 63's with shorterbeds and some with longer beds. But this truck I have looks like a 64 or a 63 long bed. It has an inline 6 if that helps. I was told its a 63. I'm only 22 so I wasn't around when they were made