I’m hoping someone can help solve a mystery about this Wood & Son “Colwyn” butter pat.

The backstamp reads:
• WOOD & SON
• COLWYN
• ENGLAND
• Rd. No. 348702

I’m trying to determine whether the buff/yellow color in the center and around the border is original factory decoration or something added later.

A few observations:
• The buff color appears in every border reserve and in the center medallion.
• In bright light, the center clearly shows what look like brush strokes, making me wonder whether something was brushed onto the surface.
• The buff color has a slightly different feel than the surrounding glaze, but it isn’t thick or obviously raised.
• I’ve tried isopropyl alcohol, and nothing came off.

Has anyone seen another example of the Colwyn pattern with this buff coloring? Was Wood & Son known to hand-color or apply a buff wash to transferware of this period, or does this look more like a later enhancement or restoration?

I’d love to hear your thoughts or see comparable examples.