Ruger Model 77 Question!

Picked up a Model 77 SS w/Synthetic Stock in .223.
Has "Old Style" Synthetic "Skeleton" stock with RUGER embossed on side of stock.
As new rifle and very clean.
Question: It has: WHITE "Inserts" in the forearm and pistol grip.
I've seen black, green and walnut inserts--But never white.
What's up?
And what can me?
Thanks