No such maker. However, if it is Harrington and Richardson, you will need to see if Cornell Publications still sells a book with H&R sn information.
25-100 USD
Cornell Publications may have a book with sn data.
Depending upon overall physical and mechanical condition, that rifle will be worth, at RETAIL, between $75 and $150.
I have purchased them from $225.00 to $450.00. The longer 999 version which is the Chisholm Trail Commemerative is worth up to $650.00.
1971
50-100 USD
Blue Book of Gun Values will help.
50-100
20-100
50-110 or so
15-150 USD or so
Consult with a good gunsmith.