If you opened your mailbox one day and found that someone had stuffed a deer head in it, wouldn't you maybe tell someone about it, such as the police?
I think the police would say to call Animal Control, and I doubt they would have 35 year old records.
I still find this allegation very hard to believe. However, I will defer to the deer hunters as to how likely it is that a deer head would fit into a roadside mailbox.