Charles:
As usual, I am going to diverge from some of the popular opinion. What is there is essentially the Cub-54A belly mount. I can't see much else that would pertain to the front mount but then it depends on what you want the blade for. The blade is upside down and you can clearly see the cutting edge and the trip spring and frame. Looks solid. The Substitute drawbar may have been custom made (mine is and I have no fears with it at all as it was made according to the drawings on the server),
The other item that is there appears to be a wing for the plow and if so that is different. My thinking is that the other parts for the front mount, which this extension wing is obviously for must be in the pile of cultivator parts. Or it may be for the belly mount position and the wing
I don't know.... I kinda like that extension. I really would like to see how that looks mounted up. But all the other front mount parts must be there to make it worthwhile. I think it is worth the $200.00 ... but that is just me and my fabricator brain taking control.
My first blade wasn't exactly factory but it worked real well and I paid $150.00 for it. When I sold it, I managed to make money on it. Mind you I had it and used it for a couple years and painted it. It was well worth the coin I spent. This one by the pics is complete in the belly mount version, but I am not sure on the front mound.
This kinda reminds me of your mower project... a neat idea. Others may not agree, but one must have a bit of vision when looking at stuff like this. I know that I paid almost as much for the missing parts as I did for my other Cub factory blades and still didn't have it all complete. The parts you are missing are usually available on

and can be had reasonable.