Indeed - however, the order their names appear in the 'characters.txt' within the game's files appears to shed light on which is which:
View attachment 9520
As these two names do not correspond to any of the NPC's who have their names formally identified in-game, I am assuming these are indeed the two Blue Spiders members - so we have their full names as well! (although, is 'mumu' really meant to be Gao's given name? The fact its all in lower case is strange...)
Assuming this listing is following the same order as 'GRA' and 'GRB', this means
Li is the bald guy, while
Gao is the bigger guy with long hair.
Oh and I also forgot to mention - Xiang and Lu's full names are confirmed in the same .txt file :)
View attachment 9521