The supplier of the OEM gel coat was probably Ferro. They seem to still be around, part of another corp.
In reality, even if you were buying a little container of your boat's exact product number of gel coat back in 1980, it would not (totally) match the OEM color. Every batch is very slightly different.
(Learned from experience.)
Gel coat fades due to UV, and also will change some with long term cure-out.
Reply #3 is the useful answer for you.
After all these decades getting a color match will be very difficult, even for an experienced repair person. I have tinted new gel coat to match our boat's original color and come close; several years later I could see exactly where I had done the work. Ditto for repairs done by master craftsmen in my area.
Doing a strong repair and getting the color to match will be a great learning experience for you. Satisfying, too. Just do not be too disappointed if the results are slightly imperfect.
And, about the color "white"..... there are about 50 shades of white... or maybe 100. When you buy some "base white" gel coat to start tinting from you may be surprised at the whiteness of the product!
