Hmm, I hope it comes with both main seals. Also, there are a ton of other gaskets that the toyota kit comes with, including oil cooler (x3), timing cover, EGR pipe, and (if you purchase the 92-93 kit) exhaust pipe gaskets and turbo gaskets. I think I can see the oil cooler gaskets in the picture, but I can't be sure. Note that the 1990 toyota kit does not come with an EGR to intake manifold gasket or a throttle body gasket, while this one looks like it does. It would be nice for them to say intake manifold gaskets, since there is one for each side of the T-VIS.
Personally, I would trust the paper gaskets, but not the valve, cam, or main seals. But, then there is no point to getting the kit. Put it this way: do you want to pull the engine to change a leaking rear seal?