stocks are the same for any model 12 or 121, try e-gunparts.com or watch on gunbroker.com.
There are people making them new as well for example
http://macongunstocks.net/remington_model_12_or_121_2_piece_riflestock_96.html
http://www.gunstocksinc.com/web_pages/Plate-pics/Remington-Stocks/Remington-Rifle-stocks.htm
You can also try e-bay. Keyword Remington Model 12 and see what you might find.
Remington didn't make a Model 12-2 but Model 12-A-F & and CS. But the value is GREATLY dependent on condition without that it's anywhere from a 200-1,200 gun NIB.
Which model 12-a, 12-b, 12-c, 12-cs? But it's mostly about original condition, condition, and condition. Without that it's 100 - 1,500.
Sounds like you talking about a Remington Model 12-A and a 12-CS. 12-A - 1911 12-CS - 1917
Well you can't asked when it was made based on the serial without providing it!
1924 It's date codes on the barrel see related links for information on the Remington Society of America.
Remington made neither a shotgun or rifle model 1890, sounds like you are might be talking about a model 12-C or 12-CS pump rifle. Until it's identified correctly and a GOOD description of it's condition, valuation is impossible.
None of them say. 22 short, long, or long rifle round barrel 12-A octagon barrel 12-C 22 short (octagon) 12-B 22 Remington Special (octagon) 12-CS
They are always selling reproduction manuals on e-bay for 5 bucks or so.. I should put one online on the Remington Society when I get a chance....
I'm guessing your talking about a Remington model 12-CS pump?If so it was made in early 1915.
Unmarked that would be a Model 12 (-a,b,c,d,e,f,cs) depending on barrel type, ammo, etc, made in 1919.
Remington firearms are dated by using a 2 or 3 LETTER code stamped on the barrels, not by a serial number. This is a link to the Remington Collector's website showing the letters and their location on the barrel. Good luck! https://www.remingtonsociety.org/manufacture-dates/
12-cs? 22 Rem (WRF) not 22lr? Depends greatly on condition, but unless it's excellent to mint probably not a lot over 300-400.