It is probaly oyster white,take it from me , I am in the canvas bidness, and my customers want an exact match between the material I use , and the gelcoat, sometimes that is not possible, but we do the best that we can do.
Problem is they keep changing the whites, and the off whites on us, with no notice, and we play havic with that!!
But as said before, get some color samples from the marine paint store, and try to get a CLOSE match!!!
Good luck!!!