The stock inlay on that gun is maybe gold. Heck, it could be brass. Looks a little too yellow to be actual gold.
But I would suspect it is not original. The inlay is not the correct shape. It is basically round and not Oval.
It is just not in any way standard for the grade.

I think it was for sale on the forum recently, two barrel DH set.

When silver tarnishes it turns nearly black as do the crest plates on my C's and D's as for the crest plates found on V"s - G's they are german/nickel silver and tend to dull with age as nickel does and when they oxidize it tends to be a white or light gray cast. 10K gold can be mistaken for brass and is commonly used on Britsh doubles. On the other hand 24K gold is nearly red in color as copper. Quarters prior to 1965 were 90% silver.