Browning.com has a sn function on their web site that you can use.
On the receiver.
1985
1980
A citori 325
1986
1982
i would go to the browning web site.Click on the customer service link and there should be a spot were you can research your browning citori lightning.
This is a 12ga made in 1973. It is the first year of production for the Citori Model.
It will be marked on the botton of the receiver.
In your question, you answer your question.
100-1000 USD or so
solder