Gold Plumb and Gold Plate

by Jilla
(Las Vegas, Nevada 89121)

Hi, I recently purchased a small jewelry lot at an estate sale and one of the pieces is a very beautiful rose gold diamond and emerald claddagh bangle bracelet. I don't know if it's solid gold or plated or ?

The stamp reads "18CT GP IRISH"

And I thought I read somewhere awhile back that some jewelry makers would stamp a piece with (Karat level) "GP" to represent a piece that is Gold Plumb and that "GEP" "EP" "GF" etc. were used to mark gold plate/electropate, gold fill types of jewelry. Thank you