I have the same set mounted in my 72...... and I was using them until at least 1983 when I left the ambulance "profession" !,I am sure they were used past that point...at least a few more years.....Now for the important question........
Were these kits available in the mid 80?
4 sets available $21.99 FREE ShippingWow! Can you ask him if he has a source?
As to timeline, I am guessing, but would say yes. "Sure" I used them back then.