If you are not mechanically inclined, then perhaps you should give this tractor a pass and just buy yourself something brand new with a warranty from one of the local big-box stores.
Owning a used garden tractor that is at least 23 years old means that things are wearing out and will need replacement. It will be an ongoing ritual that will require an investment in tools as well as time on forums to learn how to address the problems. For some people, this is just not what they want to deal with and I think that you should be told this up-front.
For those who are into mechanical issues and are not afraid to get their hands dirty on a regular basis, the ownership of a Case GT can be very rewarding thanks to the abilities this tractor has over anything sold in HD, Lowe's, Ace or other places including Sears.
The replacement cost of the basic 446 is about $7,000.00 today with the deck. They are a high quality tractor and that's why it has lasted for all these years. If the Utility Blade is brand new and is an OEM blade, then the asking price for this tractor is quite reasonable, in spite of any minor issues it may have. However........ paying some shop to repair this tractor will get old and very expensive. Doing the work yourself is the only reasonable alternative.
Give this some serious thought before making the plunge.