I think that $1900.00 is a fair price for a 60" Mower and a late edition Cub that purrs like a kitten. Most of what you describe is a cheap fix. Fenders are available - in fact there is a pair for sale over on the ATIS Forum for 60.00. A used seat can be had for as little as $25.00 and the rest is just a little labour.
I just paid $850.00 for a 1947 with a POS seat, so-so tin, so-so rubber and a Massey Harris Pony carb on it. I know I got a good deal
Nothing else came with it.
So, yeah, it is a fair price. Jump on it. You WILL be glad you did. And, just think of all the fun you are going to have putting it right.... gotta count that factor in too!