Jammy.... The ignition system is called a "Magneto Capacitance Discharge" system, first introduced in various 2 & 3 cylinder engines in 1972 I believe... BUT... really took off in 1973, being used (if I remember correctly... not that it matters) in all the higher horsepower models, the highest of which at that time was the 135hp model..
At that time, I mentioned to one of the higher up OMC reps "I believe that ignition system is the ultimate!"... and apparently I was right as here we are 46 years later and are still using the same ignition system. The design of some of the components may have changed in their appearance,,, BUT... it is still the "Magneto Capacitance Discharge" ignition system.
Bottom line.... whatever year those ignition components were manufactured is of no consequence... it's a up to date ignition system.
Some engines are a product similar to a song by Johnny Cash about a fellow working in a GMC Cadillac producing factory who took parts home daily in his lunch box for years on end... and finally he got the parts all assembled into one Cadillac automobile. Registering it must have been a real hassle as Johnny sang it as a 1948, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64... and where it ended I've forgotten! BUT it was a mighty fine Cadillac I'm sure.