I don't intend to upset you or anything but... I see this a a failing on your part. Perhaps if you had stepped up earlier - and OFFERED them something for the slides, etc. then they may have thought about it - and you may have them in your possession right now.
Or did you? If you did - then, yes, they were not interested in the money.
If you didn't... why not?
I had made sublte suggestions to my Mom in the past, but given the fact that I am Apostate(tm) she did not even want to give me an extra "Aid to Bible Understanding" book they had just sitting around, new and unused. True, I never pressed the issue, but it was obvious that there was no way the Photo Drama would end up in my possession AT AN PRICE. True, I never offered them money, but if I know my parents, it wouldn't have made a difference. Having said that, I already feel like I failed the XJW community in this respect.
~Quotes, of the "Flinched On The Objective" class