This looks early 70s to me. Just something about the styling and the font used for the Turner logo on the plastic catcher. Speaking of, why does it droop like that? Interesting to see Mayfair gold. Does this suggest a third party paint supplier?
I hope the bore isn't worn oval and you can successfully get it to run. I get the feeling older fours present a challenge to get running.

Ahh, if only victa had kept producing the thumblatch catcher series, they would be in better shape today!