I went and looked at this today. The rear cutting edge is welded on to the hinged back, the front facing cutting edge is bolted in. Rear blade is bent but could be straightened out I believe.
Not worth the trouble so let it be.
Saw another blade, a Massey-Ferguson model MF18 I think it was. Quite a different setup for the rippers, the whole bar rotates down to put them in play. Looked like a very heavy blade but well used and asking $550 !!, I let it pass too. People are crazy with their prices around here. Guess I'll be waiting for the next auction in New Holland, PA. 50 miles away but beats the prices around here.