Dr. Grodin says he has been working on deciphering the Ancients' logarithms to explain how he can tell what a piece of equipment does. Logarithms (mathematical functions that are the inverses of exponential functions) would be useless and not require a lot of "deciphering". Presumably, he means he has been working on deciphering the Ancients' algorithms. Dr. McKay should definitely have known better as well.
Throughout the series, Atlantis standard procedure seems to be for team members to remove their insignia and nationality patches from their jackets when off-world. (This is presumably to keep Atlantis's identity a secret from others unless otherwise told although it seems partly pointless. The Atlantis insignia and uniforms would obviously be a giveaway, soon well-known amongst the people they encounter, but the national flag patches are merely abstract symbols and would mean nothing to those people.)
When Sheppard and his team meet the abbot in the village, Sheppard is seen to be still wearing his jacket patches (although they are removed in a subsequent scene).