It was made in 1977
No
No
Call Browning with the serial number.
The 2 letters PP in your serial number sequence indicate that your Browning BT-99 was made in the year 1988.
Call Browning with the serial number.
1978
Right
100-1000 usd
No serial number = no way to answer.
Go to Browning's site, click on Support then date your firearm.
1987