Ranger was a Sears Roebuck trademark. The guns were manufactured by several makers. If you have a model number, it may be in a cross-reference list. See http://www.e-gunparts.com/crossref.asp
Savage/ Stevens
Savage/Stevens
Marlin
Marlin
Marlin.
No known published sn data.
Proofhouse.com has store brand chart
Marlin model 80
No known published sn data.
Proofhouse.com has a store brand chart that might help.
Marlin Arms. Same as Model 81
No published sn data.