Let's just say you are talking about 14" barrels. Around here I can get right now a 41 or 44 for $150 to $175 used.
The 375 only comes in 12" with factory break that I know of and I can get one like new w/sights for $195. Now the scopes are harder to say. I paid $100 for a 2x last year for my 45LC in a Leupold. I think the least you could get into a Burris 2x is for $100 if it is in good condition. If the bores are bright and no dings I would say the .375 w/lighted scope would be in line. Not that I would pay that but market value around here. I would say the other two would be more like $250 and he would probably come down to that if he is wanting to move them.
If the frame is a easy open with the sliding bar in the hammer or the toggle switch on top of the hammer and it is clean, it is well worth that with you not having to pay any shipping. The older frames have a pivot pin that the trigger assembly pivots on right at the bottom front part of the frame. The easy open frames have the pivot pin over the trigger. The older frames are okay but to have it changed over by TC to the easy open you will have to drop another $50 or so.
I bet you could lay about $800 on the table if you wanted all of the items and walk out the door with them. Even if you didn't want all of the barrels, you could sell the ones you don't want and recoop some of your money.
I would like to buy the .375 Win or trade you a like new .223 Contender barrel towards it. You could keep the lighted scope.
Mike