I have seen many aftermarket and/or different year armrests in the '60-'66 Chevy trucks. Although not all trucks of this era came with armrests from the factory, the panels can be drilled to receive the armrest of your choice. If you want to use the factory holes, you can fabricate armrests from glued up wood stock, ie oak or maple. I did a pair of custom armrest from red oak. With a bandsaw and an orbital sander you can make about any size or shape you want. If you use a tight grain wood like maple they can be sanded smooth, coated with sanding sealer and painted to match your interior. Good luck with your armrest project.
