Boy, this is a really tough one to give a definitive answer to. Actually, pretty much impossible as there's just too many variables. The first being fresh or salt water. After that, there's a myriad of questions and things to check out. For example, what Vero said above about the lower units and water getting in... Well, if water did get in, it's possible that they'd be OK. But it's also just as possible that they're shot. It's just too hard to say. Best to err on the side of caution, though.
What I can advise, though, is don't buy the package hoping the engines will work with only a little time/effort/money put into them. But they do have some value - to the right person. If you buy the package 'wisely', you should be able to keep the trailer and sell off the boat and motors and get all of your money back - maybe even make some if you're lucky. But the key is doing the advertising correctly to find that "right person". Don't plan on it being a quick turnaround.
On the positive side, I do know of some engines that have been submerged and then brought back to life and lived happily ever after. But don't enter into this deal with the expectation that this will be your outcome.