The feasibility of finding an exact replacement part for a 32 year old boat is virtually nil. Your best shot will be finding a similar item from a catalog or on line. West Marine generally has a good selection of cabinet/window/door hardware at their larger stores. Brouse the aisles and see if you can find a similar piece of hardware. You could also look for it at some of the used marine parts and consignment stores around the country. Take a look at www.sea-dog.com
, these two companies are the biggest suppliers of this type of hardware.