Being a person not knowing much about plaster casting of footprints, would DNA material of the creature seen in Patterson's film be found on the plaster cast that were made of the tracks? God bless.
Nightwalker

Wouldn't work. The odds of any bits of skin, hair, sweat, etc. actually being left begind in the print, then being incorporated into the cast are very, very, very low. Especially after 4 decades of handling, recasting, etc.
Interesting idea though.