Here's what the 1963 black plates looked like on my 1960 GMC back in the early 90's.
As noted on the license plate link above, commerical vehicles (including all pickup trucks) required commercial plates (including those that were privately owned). These had a different numbering sequence than passenger cars, which may be important if you are doing a restoration.
Rumor had it back then, if you did not run commercial plates on a pickup and got caught with so much as a loaf of bread in the bed, you were subject to something like a $500 fine. I have no way of confirming if this was true or not.