Thanks for your help Alf, I was sorta thinking 1970.
kmitch & TAB, I feel the vibes coming through my laptop, but you'll feel better knowing that I had to give almost $300!!!! for it!...and it's only in about 98% condition

----OK perhaps 99......and a 1/2
edit: I just came across this:
4K1,628 – 4K54,104.....1973
5K6,617 – 5K73,962.....1973
4K54,105 – 4K99,999....1974
5K73,963 – 6K58,917....1974
7K1 – 7K26,043.........1974
7K26,044 – 7K70,577....1975
6K98,918 – 8K20,763....1975
stating that if it were a 'K' frame it would be 1974, there was no info about J's but it might make sense that they used the same system?