I wouldn't be concerned , a once over checking for corrosion would be in order paying special attention to the electrical cabinet .
Resell value never entered my mind when I bought my 440 I can see your concern there . But if I was buying a used machine one of the things I'd do would be to call tormach with the serial number to double check the purchase date .. And try to make sure it isn't a lease machine someone is trying to defraud