The only difference between the DS2072A and DS2072A-S is the -S version has the built in function generator. Other than that the hardwares are identical, they use the same exact firmware, the hack is the same for both. I have a DS2072A-S (yes it is hackable, seller doesn't know what he talking about), however I would recommend getting the one without the builtin generator because the builtin generator is a pain to control. Unless you just don't have the space for a separate standalone generator, don't waste your money on that option.
Edit: Wanted to add, don't pay extra for the seller to hack it for you. Its literally a 5 - 10 minute process that you can easily do yourself.