Not sure, but it appears your 39 might be blued over the color cased receiver, and lever? If so, that will hurt value quite a bit. Bolts and hammers were blued, but not receivers and levers.
If this is cold blue, then rust remover will take it off and leave whatever case colors were underneath. I've done this on old Marlins that were blued, and if they didn't polish the metal first they come out fine. Even when hot blued the bluing still comes off and leaves whatever case colors were there.
Looks like your 39 had a tang sight also,as those screws are sight base screws, and not the usual factory plug screws.
And your barrel has the "Corporation" rollstamp, so it's one assembled soon after Frank Kenna bought Marlin from bankruptcy, and those barrels were used for a year or two until they switched to the newer rollstamp. Yours also has the Marlin "Bullseye" in the stock that started around 1924, and was used up until the Depression.
Some bolts were replaced by the factory to High Speed, but your great picture shows yours still has the low velocity style bolt, so standard velocity, or target velocity ammo should be the only ammo fired in it.
If this gun had strong original case colors they go in the $1500-$1800 range. If there's bluing over the case colors it's half as much. If the wood finish is non original, then that's a little less. But yours appears to be the high sheen used then, and wood to metal fit looks great too.
