IIRC H&A used the "XL" model designation liberally on a wide variety of revolvers, sort of like S&W is now doing with the once-proud Chief's Special name. It used to be a revolver. Now it's also a series of semi-autos, a rifle, a toilet plunger, a bicycle, a mechanical adding machine, etc...
This is an XL3 single action spur trigger:
And here is an XL model double action:
XL was even used on a series of large frame revolvers chambered for cartridges like the .44-40.
So, don't get too hung up on the model designation.