To be honest do not be surprised at the offers,
Continuum Season 2 DVD Box Set, if this is just a box with 1000’s of stamps in it and not sorted in any way,
Doctor Who Season 6 DVD Boxset , then the dealers could easily miss something while quickly going through it. It is also very time consuming for them to have to sort through it later.Here is a link to a site with some stamp shows for every state but I doubt if it is complete,
Fairly Legal Seasons 1-2 DVD Box Set , you may want to try to do an Internet search for just your state.I would at least try to check some of the earlier stamps,
Flashpoint Seasons 1-5 DVD Box Set, to see if there may be anything of value. That way if you do find some stamps of value then you can at least point them out to the dealers.