i know some people who got in some trouble with that kind of stuff. I asked some local people around me, and they told me it can go either way. If the equipment was purchased by a company no longer in use, then who ever's land it sits on, owns it. Its kind of like buying a camper, if some people used the camper before and left some valuable items in it and they sold it, the people who now own it own whatever was inside. BUT, id ask possibly near by law enforcement, etc.

Hope you get that stuff!