Hello Shaf,
Your 280 might be 501 as indicated before (I cannont prove this now) or 542 ("dark red").
Look for the 3-digit number(s) on the plate like 542 G 542 G
(G = Glasurit, H = Herberts).
My 2 humble cents: keep it dark red. It's beautiful and not too common. Very elegant.
Best,
Achim
(Magdeburg, Germany)