Bob Jackson serial numbers are noted by them, I think for a fee they will advise you. From the graphics I would say 1972 to 1974, my best guess 1973.

Most of the imports were framesets, a shop who would import them, would also build them up, so anything goes.

If you lie this bike for size and assuming the saddle height is the same as your other bike(s) reference the length from the saddle to the bars, perhaps a longer stem on that bike is in order and or you like the bars higher on this one.