Interesting thing I found in the GX20 service manual that the top of the LCD has 4 strips of sealing just as the back, so when you set the whole top cover down it seals against those. Also in some of the pics it shows some black sealing around the top LCD frame and in others it does not. If you look at the GX20 service manual exploded view you will see part numbers A390, A391 but they are not in the description list, at least I did not see those numbers it skips it.
Now remember this does not concern your repair at all; becuase your not takig off the whole top cover, just the top lcd cover. But what is the WR seal the cover or are there 4 strips of sealing sitting between the LCD and upper body cover. Something only a complete tech mechanical freak like me could be interested in
BTW if the weather seal is those strips for the GX20 than it should be for the K10D as well, logically.