I am curious to know if you have any old 16mm films that were presented at various locations back in 1966+ (i.e. Joselyns) My grandfather
Thanks for asking! Unfortunately, we have no archival collections of 16mm or other projection film formats. About the only place I can think to refer you would be the Nebraska State Historical Society - they do have some motion picture archives, but given the challenges in curating that kind of collection be prepared for a long and potentially expensive research process. Large chunks of their holdings may not have been indexed - but if your grandfather was a local filmmaker, there's at least a chance you might find him.
Information about the NSHS' motion picture archive is linked above, but you can also call them at 402-471-4751 or email at email@example.com to learn more about their collections and fee schedules. Thanks again for your question!