Depends on the condition of the lens, usually a fungal infection if its bad will etch the coating of the lens. You'd tend to get more flare off this lens. I'm not saying you shouldn't buy, but I'd probably wouldn't
When I buy some thing, I expect to get my money's worth.
Besides, you never know what problems the lens may give you in the future, so why take that risk and feeling sorry for yourself later that you wasted money on a lousy lens should anything really happen?
The fungus may stop, or slow down inside the dry cabinet but frankly speaking, I rather not take chances.