I believe that sun in intending to make "genesis" patches available to add the extra packages to older machines. But I don't knpw when they will be available...
Chances are its probably sufficient to compare the package lists on a s10u1 and a s10u2 machine and work out the extra packages installed on the s10u2 machine and just add those.
And also pick up all available patches.
But I make no guarantees.