Model R-12
It is a sight for a Remington model 12 pump .22 If you have one I will buy it.
Depending on condition the blue book value is between $250 and $800
Lyman
Impossible to answer without knowing the model of the rifle.
I had a dealer offer me $150-$200 sight unseen for mine.
Lyman is currently only producing the #2 tang sight, which is not designed for the Winchester 9422. Marble's makes a tang sight for the Winchester 9422. The LR version requires the 009812 sight and the 9422 Magnum requires the 009837 sight. sales@countrygunsmith.net
yes lyman made them for Sears
The "P" designates peep rear sight & ramp front sight, not sure of the "G" designation.
The standard mod 70 had a Winchester bead front sight on a ramp base with a sight cover. The standard rear sight was a Winchester 22G open sight. The rifles chambered for .375 H&H Mag had the Lyman 6W folding rear sight. Model 70 National Match (chambered for .30-06 only) had a Lyman No. 77 front sight on a forged ramp sight base and a Lyman No. 48WH rear sight. All receivers were tapped and drilled for popular scope and iron sights. The Model 70 Super Grade had a Redfield full gold bead front sight on a ramp with sight cover and a Winchester 22G open rear sight. (with acknowledgement to The Gun Digest, seventh edition, 1953)
Find the serial number and google the Remington sight. They should have records of when the weapon was produced.
www.e-gunparts.com
Someone at rimfireforum.com should be able to help you.