Most diamond tuck interiors were hand stitched, otherwise needle in a haystack, you don't want the manufactured stuff anyways, (I am not sure its made in marine grade anymore) the interior shops can duplicate anyting and it will be a lot tougher than any pre pleated stuff out there. Try and find someone who does interior work on Lowriders, those guys are very talented and could probably do it period correct. Just make sure and let them know it needs to be "marine grade" vinyl, otherwise it won't be as mold resistant...
Good luck!
GT
