Kits for the 1963 models are available from OPGI http://www.opgi.com/cutlass/1963/interior-accessories/seat-upholstery/
but I don’t know of anyone reproducing 1962 seat upholstery. When I did my 1963 these kits weren’t available yet. So I went the SMS Fabrics route and found a good local upholstery shop who used the original seat upholstery as a pattern. I had good luck with SMS but others have received batches of material with inconsistent coloring. The two-tone colors were a problem for at least one other person who frequents this website. There is another thread on this forum with seat upholstery as the subject. Good luck with your project.