67 N15cs

Can anyone tell me the correct oil capacity for the longer fork on the N15cs please? Manuals state 150cc but that is the same as the shorter Commanfdo forks. They top out unless you up the amount to 170/180. Are the G15 forks the same or is it more due to the longer tubes and damper body?
Thanks Neil.

Wonder if it’s a “Scrambler model?”