None of my Savages have jeweled bolts and they date from between 1908-1930. I'm guessing when the rear sight was added the action had to be disassembled, and it was jeweled at that time.
The 99A came out in 1926, but is only listed with a 24" barrel, but barrel length was an option on earlier models for $1 for each inch up to 30". If only these old rifle could talk, that would answer a lot of questions!! :)