Seems likely. Gamzee must have ascended somewhere and it doesn't like there'd be a rage bed in the trolls' meteor or the alternate universe kids' session.
EDIT:
Or Gamzee just sewed himself up some bitching duds. The man's a sucker for a codpiece.
There's also the possibility that he ascended a long time ago; we have seen something that looked an awful lot like his quest bed would beforehand.
Steam ID: The Great Squark
3ds Friend Code: 4571-1588-1000
Currently Playing: Warhammer 40000, Hades, Stellaris, Warframe