I thought the right was #1 but I could not confirm with the manual. Anyone know?

I am having problems with installing SV gauges on my GS.
Something is wrong, besides the difference in the SV wiring diagram and the actual wiring.

I looked in the factory service manual and could only find that the left carb was shown as the #1 carb, and the right as the number #2, and that is all. I would assume that the left cylinder is #1, but have no evidence to back it up

Ditto.  The left cam lobe leads the right lobe by 90 deg...180 deg firing order w/cams spinning 1/2 crankshaft speed...so left = 1, right = 2.