Were the rear turn signal stalks shorter on the AT/CT bikes?
Picked up a set at VMD this year for my friends 71 CT. Looks
good on the bike with them tucked in a little like they are. The 
ones for the 250 are longer and the wire runs differently.

My original AT2 are approximately 1 1/2” long stalk

Dont know exact the inches but my LT2 rear turn signals stem are longer than AT and CT.

Same basic indicator bowl/lens for Yamahas of this era, but at least three different stem lengths. Some bikes also fitted with indicator extensions, presumably to make them more visible.

Some bikes had the indicators earthing direct to the frame, others were rubber mounted, with individual wires earthing them into the loom. Another variation was the earth wire being integral to the indicator, with its own exit point out of the stem.

The amber/red indicator lens changed from deep to shallow at some point.

I believe the shorter salk ones were for the AT and CT for use with the rear buddy rack. Mt DT2, without a buddy rack, has the longer salks.