I think what he is wondering is if the LIM and UIM can be removed as one unit so that he doesn't have to replace the UIM gasket again. Correct me if I am wrong.
I am not sure if there are any bolts under the UIM that would necessitate the removal of the UIM. If there are not, then I don't see why you shouldn't be able to remove them as a unit.
If you do have to remove the UIM, I would suggest at least replacing that gasket for the reasons mentioned above. It'* been 3 years, so even if it still looks good, it'* good insurance/piece of mind to do it rather than reuse the old.
And I like the spray bottle idea for removing the excess coolant. Never would have thought of that.
2007 Saturn Aura XR | 1970 Chevy Blazer 4x4 | 1970 GMC 3/4 Suburban 4x4