1 of 51 ! can it be possible :

So ! lets start this : 24 817 duster 340 1970 were made:

3018 were shipped for canada : 29.66% of all duster 340s were 4 speed cars ,
so.. 3018 divided by 29.66 % = 895
895 x 5.7 % ( Galen Govier production of fj5 340 dusters ) = 51

51 made fj5 duster 340s sublime green 4 speed for canada , i dont know if you guys have other infos on this but i think that its pretty rare and close to be very accurate

That's not right. You can't assume percentages of percentages.

More 340 cars were FJ6 than /6 grandma Dusters.

Maybe all 5.7% of the 3108 Duster that were painted FJ6 where 340 4spd cars. That would be 177. Or maybe most were like 150.

Is the percentage of FJ6 painted car just for Canada or is that a US number you applied to Canada numbers? Or total all US and Canada number applied?

I think even the most popular paint colors where only like 10-12%. So with your reasoning that's would make even the most popular colors 1 of 100 for 4spd Dusters.