Based on the photos you have it is really hard to tell if you have a regular 54A blade or an L54 blade for a lo boy. The only tell-tale sign is the pressure spring rod assembly, which the one shown in your pictures looks like a standard 54A assembly. Here is a comparison pic from TM Tractors website:
Based on this I would say that your pressure spring assembly is definitely from a standard 54A, not a L54, and therefore I would assume that it would not work on your lo-boy.
However, I also notice in your pictures that much of the hanger assembly is not there, and the previous owner has fabricated a hanger assembly, looking like it mounts to the rear final drives instead of hanging from the bolster. So, again, I'm guessing that it was fabricated for a standard Cub, and since the mounting points are all different on a lo-boy, it would not work on your lo-boy. Based on your photos, some missing parts include the lifting lever:
And front axle hanger assembly:
Both of which are different between the lo boy and standard cub.
Having said all of this, since much of the hanger assembly is not there, you probably have the opportunity to mount it on whichever tractor you want. It looks like it "should" mount on your Cub, as the previous owner stated, but it's obviously not all there . You could find/purchase the components you need to correctly mount it on either tractor, whichever one you want.