BT99
500 uSD
Japan
100-1000 usd
1988
1971
2003
You must call Browning as the sn you gave does not follow normal convention.
100-1000 USD
If you go to browning,s home page there is a way to age your shotgun there.
50-650 usd
Browning doesnt show the BT99 as a 299 model code. They list the BT99 as a model 149. Below is the link to the Browning codes.