The 90 lever will certainly fit the 175/200 gearshift shaft (all Bridgestones use the same gearshift spline pattern), but the 175 lever is bent out further than the 90 lever to clear the left-hand carb cover. I think you will probably find the 90 lever will foul the carb cover, and as the lever is a casting it's quite likely to break if you try bending it to clear.
If you find a 90 lever really cheap (i.e. for free) it might be worth a shot, but otherwise it's probably best to wait for the correct lever to turn up.
Graham