Peter, it's obvious that the auctioneer doesn't know movie posters very well, but I find it hard to believe that a guy who has 2 rare French King Kong posters worth a lot of money doesn't have other like-value posters. Also, it's obvious he has lots of non-movie posters that could add up quickly
here is some blind estimation that I like to use
7000 posters
if he has:
1000 posters worth $25 (all prices quoted are retail prices) = $25,000
1000 posters worth $50 = $50,000
1000 posters worth $100 = $100,000
1000 posters worth $250 = $250,000
1000 posters worth $500 = $500,000
500 posters worth $1000 = $100,000
500 posters worth $2000 = $1,000,000
200 posters worth $3000 = $600,000
200 posters worth $5000 = $1,000,000
======================
6400 posters ............... $4,025,000
or how about this
7000 posters worth an average of $100 each = $700,000 then add all kinds of money for $500 posters, $1000 posters etc until you get to the KK posters which should be worth $50k-$100k each and all kinds of other posters worth something in between $100 and $5000
it adds up very quickly as a retail value