DMW, just curious-- how did you figure it was made in 03- the SN itself?
Chuck-- yes, you can use the 3PH with the deck on-- what you have to do is raise the deck, then screw the mower height adjusting knob all the way up (max height); there's a threaded rod and a stop below the floor that sets mowing height, and that should be able to hold the deck all --or nearly all-- the way up. I do it that way for the very short time I need to use the tiller (really small "garden"), but ordinarily I just remove the deck; it's not hard to do. I also believe the snow blade is still the same, even for the new model tractors, and should still be available- but you'll have to get the mid-mount PTO mounting assembly with it, which makes it kinda pricey.
All the comments DMW made about the earlier models seem right on the money, from what I've learned on this site. Good luck! WBB