Page 5-21 towards the end of the book - Sundry Items for Rifles - There is a good list of various items and extra work available with pricing.
The reason I am reaching out on this subject is I have about run out of research information in an attempt to find a, or I guess I should say another gold plated model 99. The one I am researching has a Savage factory letter calling it "a special and unique model 99 K " shipped April of 1928. Receiver dates to (probably) mid to late 1927. Rifle is entirely gold plated save the barrel and seems to have a little bit of extra engraving.
At this point I am thinking it is the only one known.
Hoping someone here at the campfire has seen or heard of another or can comment on rarity.