20 gauge semi "info please"

[Whitepine]

I aquired some firearms and am looking for info on them.
First is a 20 ga. semi auto made by SKB arms. Its called a Xl 3" Mitsui + co.
Secound is a Smith and Wesson 1000 m semi auto 12 ga. 3" full choke.
Third is a 10 guage double 10 guage mad by american arms co. Itzian Spain 3 1/2'
Any info including how much they are worth would be appreciated. Thanks!

 

[12magnum]

your 20 ga. SKB was manufactured in Japan from 1968-1972. v.good cond.$200.00,excellent $250.00 , perfect $325.00. s&w mod.1000 DOM1977-1984, v. good &255.00,excellent $285.00 perfect $330.00,i can only find three american arms (trade name) 10 ga. sxs. best guess is a TS/SS sxs made in spain DOM 1988-2000, vgood $375.00 Excellent $435.00 , perfect $625.00