Stevens 620 Trench gun value

Any ideas on a current value for a nice Stevens 620 Trench Gun? Overall a very nice gun with about 92% original finish with some wear on the tube and a little normal wear on the sharp edges. Very nice plum color still on the bayonet lug. Barrel is matching but am a little hesitant to pull the stock off. Definitely looks original to the gun...

Stevens 620 Trench Gun - Album on Imgur

Any assistance would be appreciated!

Hey I think I know that shotgun.

Hello,
A very nice original example! It's in the first half of the second production block so the non "S" marked bayonet lug/heat shield is probably correct. Easily $3000-$3500.