All have given sound advice. If you check the AGCO web site:http://agcopartsbooks.com/PartsBooksN/login.aspx?ReturnUrl=%2fEpsilonWeb%2fbook.aspx%3fbook%3dagco%2f79001544&book=agco%2f79001544
Log on as Guest and search under AGCO Allis WD45. Two MS categories for WD45 lump TSX-561, TSX-464 & TSX-773 together while TSX-871 is listed separately, likely later engines. But it looks like the nozzle you want is common to them all and is AGCO part # 70226460, so it should be available.
If other sources don't have it, try Steve at 973-632-5596