The blade looks like it is in good shape.
Although I can't specifically answer your question, I have a pretty similar setup. On my YM169d I have a JD 375 blade. The 375 blade seems to be a bit shorter and have a different under-carriage beam/setup. My concern for your 165 and the 650 blade is that the under-carriage beam might be too long for the tractor wheel base. Can you take measurements and have the seller confirm lengths, etc.?
Also, does your 165 have 4x4? If not, I wouldn't try pushing a whole lot with the blade-- for instance, even in 4x4, the 169d can only move about 10" of snow before beginning to struggle...
good luck! -Art
