Yep! That's what I figure, a little dice and splice....
I remember even in the '60's that picture was floating around and people were arguing about whether it was real..then you would hear all of the "personally witnessed" stories..."I know they get that big. I saw one last year that stretched all the way across the blacktop! His head was in one ditch and his tail was in another!"...or..."My neighbor ran over one that big a few years ago and it bit the tire on his car and gave him a flat tire..when he took it in to have the tire changed the fang was still in the tire. The guy changing it didn't know it and got scratched by that fang. He nearly died at the hospital."
That and the stories about the water skiier falling off the skis and into a "nest" of "Water Moccasins" and being bitten, like 500 times before they could pull him out "He still had Moccasins hanging all over him, they had to beat them off of him with a paddle!"
And, of course, the one about the kid digging up worms to fish with and accidentally digs up a "whole coffee can full" of "ground rattlers" and said to his dad "Dad, these worms keep biting me!" Of course, tragically he dies before anyone can do anything....
If you would try to point out that these stories were obviously B.S., these people would rabidly defend the authenticity of them, although they could never produce any evidence or anyone that was personally involved...it was always a friend of their uncle's mother-in-law's neighbor's cousin.