There are no universally accepted ethical standards. Each individual has their own level of conscionable action.
The truth is, unless you have inspected his collection, neither of you really knows its' value. You may find that your example price per would be less than favorable to YOU!
Personally, it would bother me if I didn't forewarn the fellow that he could be sitting on a substantial windfall, provided that is indeed the case. If he decided he would rather just get rid of them all at once than go to the trouble of 'parting out' his collection to the highest bidder, I wouldn't feel badly about offering less. After all, you're taking all the thorns with the roses, so to speak.
Have a close look first and then be honest about your findings. The man can then make an informed decision and you can feel confident that you did the right thing.
The truth is, unless you have inspected his collection, neither of you really knows its' value. You may find that your example price per would be less than favorable to YOU!
Personally, it would bother me if I didn't forewarn the fellow that he could be sitting on a substantial windfall, provided that is indeed the case. If he decided he would rather just get rid of them all at once than go to the trouble of 'parting out' his collection to the highest bidder, I wouldn't feel badly about offering less. After all, you're taking all the thorns with the roses, so to speak.
Have a close look first and then be honest about your findings. The man can then make an informed decision and you can feel confident that you did the right thing.