The '60-'66 Chevy/GMC factory bench seats are the same, but slightly different than the '67-'72 Chevy/GMC bench seats. If the later years fit, I guess you can use one, however, to ensure a proper fit, I would try to find a factory bench seat from a '60-'66 Chevy/GMC truck, to be sure. Also, there two different seats available...standard and Custom Comfort, which has thicker padding & fill.
I found one for free on craigs list in my area a few months ago. Check your local area and you may find a '60-'66 Chevy/GMC one for less than $50.00. I have had several reupholstered and I believe them to be a good quality, fit and finish for these trucks. Good luck.
