Definately Looks like a 400 bracket to me. If it was a 200 series bracket it would still fit the 322.
It'll fit.Yup a 400. I bought a 54 blade years ago with the opposite problem. It was off a 300 series so I had to acquire a 400 mount off eBay. IIRC it was off a 314. I kept the mount just in case I ever have something it fits. Haven't tried it yet but it looks like it might work on my 140.
Let me know if you any to part with it!! 🤣👍🏻👍🏻