Do you mean Tiger/Marble, rather than Tortoiseshell, John?
I thought the whit
ish bits with brown spots looks like the creamy background in Marble, so that would be a silver thing, not white enamel.
I have pretty much always thought that white did not appear until after Said took over, I've never found any evidence to the contrary, but... absense of evidence is not evidence of absence.
Obviously, I didn't know anything when I started, I can't remember when it was I realised that white did not appear until later, but it was fairly early in my learning curve.
I'd noticed there was splodgy stuff with white in that I didn't like, not anything like the stuff I did like. Then I found out that the splodgy stuff, with white in, didn't seem to appear until Said took over.