MAG imported R1's into the UK and explained they did this because they could not get HW80's, they imported around 30 or so and fitted HW35 springs to them to reduce the power.

This was 1981....so i have no clue what was first LOL

I have a real old one here, barrel was rusty though so was swapped, early 1981 manufacture, if i can find the barrel again I will post up the serial no