Your tuners look Gold. Mine are Nickle or Chrome. My Guild Script on my headstock are really yellow/or gold. This is my first Guild and not sure if it aged or was made like that. Yours looks like white pearl. Out models are only 4 years apart.
It IS possible they started using different pearloid in that span but I have a suspicion it's probably more due to yellowing of NCL on your headstock, because the body looks somewhat ambered up, nut & saddle look especially dark too.
Definitely spent some time in the sun, like my D25.
And yes we don't often note things like change in tuner plating but suspect that's "legitimate".
They were completely flexible about implementing small changes like that, sometimes planned, and occasionally simply because they had a parts shortage and used something they had on hand to get guitars shipped.
Here's a PDF to a 1990 catalog, and while I'm
certain, the JF-30 in there
does look like it's got the gold tuners when I blow it up enough, yet the text says nothing about that even though it points 'em out on the JF-55.
https://acousticmusic.org/wp-content/uploads/2016/02/Guild-1990-Catalog.pdf
Also confirms they still had scalloped bracing in '90 which I don't remember seeing before.
And assuming the catalog's accurate because even their catalogs had errors according to Hans Moust.