Identifying P-BO-20 Disc Tiller

I have this Ferguson 3point multi-disc plow. The tag shows Model P-_ _-20 and serial # 1805. Below the Ferguson it has Massey-Harris-Ferguson Limited. The only rough place on the tag is the blank spot in the model number. Can you tell me what it is? August 1, 2014

It appears that you have a Ferguson Model P-BO-20 Disc Tiller. This is one of the implements that was carried over to the Massey Ferguson line.