The 1973 Parts book lists Roadster tanks as follows :-
750, Fireflake Royal Blue, no trim
750, Canary Yellow, no trim
750, Black, single line trim
850, Fireflake Golden Bronze, double line trim
850, Fireflake Royal Blue, double line trim
850, Black, double line trim
850, Candy Apple Red, double line trim
There is no mention of the short-stroke 750s (Candy Red with no lining)
I don't have a 1974 parts book but according to Roy Bacon, the 850 Roadster colours were unchanged for 1974 with the exception of the appearance of the white tank with blue stripe.
However, we've had discussions on here about the difference between Royal Blue and Pacific Blue (the 1974 850 colour) and they aren't the same.