I recently bought a Superglide rear fender that came with a set of fender struts. I compared those struts to the FL struts I already had and they are identical.
I always thought FX struts were narrower than FLs and had a additional hole for blinkers?

 

They are Much Different... In fact FXWG is different again..
The FLH allows for the Hinged rear fender, the FXWG has to hold the Taillight/plate bracket.
the FX has fewer holes and is in fact narrower..

 

That makes sense.
I wound up getting another set of FL struts then.