Hi there, here are some guns owned by my Great Uncle, anyone know how I can find information on their origins?

(TOP) The Serial Number is: 541876 It is also marked with: REG.IN U.S.PAT.OFF -WINCHESTER- -TRADE MARK-

(SECOND) SN: 208644 Other: MODEL 1890 -WINCHESTER- TRADE MARK

(THIRD) I believe this one saw action in WW2 SN: C 19739 Other: MA LITHGOW S.M.L.E [GI] 1941

(BOTTOM) SN: K 065486 Other: .38 SPL-.357 MAG. MADE IN BRASIL

Anyone know where I can begin looking for these firearms past? They mean a lot to my family.