See if there is a model/serial number tag on it somewhere
Alot of companies make a box-framed disc and they all look nearly identical.
They are alot more heavy duty than angle framed discs and most of the ones I see adjust the same way that one does with the long threaded rods.
Knowing the MFG is really not needed for parts. They are mostly standard. And if you needed to rebuild a gang, you buy disc's and bearings by size/type....not from the MFG.
I agree, it looks like a good one if the price is right. (if you are looking to buy it)