pretty much...

Bil₃-ga-meš₃
This appears to be the more original reading of the name familairly known to us as "Gilgamesh". The apparent meaning of the name is "The old man (bil₃-ga) is (now) a young man (meš₃)". This sounds like an odd given name. Maureen Kovacs translates the man as "The Old One is Youthful", and adds" Such a meaning is inherently unlikely for a name given at birth, so it may have been given at his coronation" (1985:xxvii). It may also have been an epithet applied to him after his death. In either case, his given name is thus unknown. It is also not impossible that the name had some other completely different meaning, and the standard interpretation is an ancient Mesopotamian folk etymology.
The change of initial /b/ > /g/ took place as a result of assimiliation to the following /g/. It is not known when this change first took place; an Old Babylonian omen text of about 1900 BCE has the spelling ͩGe-el-ga.
The bil₃ sign is itself a combination of two signs, the giš-sign and the bil₂-sign.
-- Hayes, John L. "A Manual of Sumerian Grammar and Texts." Second edition, pp. 153-154.
The historical Gilgamesh was the fifth king of the First Dynasty of Uruk, which falls within the Early Dynastic II period (about 2700-2500 BCE. No inscriptions of his are preserved, or contemporary references to him, but there are a few inscriptions of his approximate contemporaries.
The first attestation of him is in a god-list from Fara, where is name is written ͩBil₃-PAP-ga-meš₃. It is difficult to say exactly how these signs represent the name /Bilgameš/; his name is spelled several different ways in the course of Mesopotamian tradition.
Gilgamesh was very popular with the UR III kings. According to Jeffrey Tigay, "The kings of Ur III regarded Gilgamesh as something like their personal god" (1983:13 n.50). Michaelowski speculates that the "Giglamesh stories were made part of the school curriculum during the Ur III period" (1991:54). In his hymns, Shulgi refers to Ninsuna, the mother of Gilgamesh, as his own mother, and he refers to Gilgamesh as his prother.
-- Ibid, p. 169
EDUCATION.