Jack,
Since we are from the same geographical part of the country I'll give you the same advice that I initially give everyone that asks me that same question!
Since there are several around these parts I'll put it this way!
How bad do you want that one!!
You already know that it will have to be rebuilt after it sat that long not to mention new rubber plus stripped and painted in order to have any resale value should you want to sell it!!
Not knowing what you want to do with it and the lack of a picture makes it all the more difficult!
If you gave $500 for it and put another very conservative $3500 in it you would end up with a very nice $4000 tractor to do nothing but pull something around with!!
If you invested another $2 to $3000 in it you would have a pretty nice Show Tractor!! Of which there are several in that make and model!
Is it worth $500? Absolutely!!
Dean