I can say that john brownings last design was produced in 1935 for the first time.
Your browning hi-power was made by browning in 1967.
You must call Browning.
Your browning high power was produced in 1980.
Browning's web site has a sn search function.
Proofhouse.com has Browning sn info.
1993
Your browning high power was made during the years 1945-1954 in which browning and FN of belguim did not keep track of the production figures of the high power.The records began with serial number 72251 which was in 1955.
SN dates to 1966.
Browning High Power
You can call Browning, you can visit their web site, you can look it up in the Blue Book of Gun Values
The 2 letters PY found in the serial number sequence indicate that your Browning High Power was made in the year 1982.
Browning's web site has sn data under customer service.