Ive got a 30 year old Pentax KM and 4-5 or so lenses. This was given to me a while back and Ive never used it. Also, it's important to note Im a state away from the camera so I do NOT have it right infront of me. What are the chances that these lenses are still good/usable? Could I use these lenses on a new Pentax DSLR? Thank You!