In a way, yes. The individual colors themselves may not serve as a direct symbol for anything, but like everything else in the room, the way that the characters interact with them is telling of their individual personalities. This is reflected when Garcin asks if the furniture is the same in all the rooms, to which the Valet responds, "No, we cater to all types."
When Estelle enters the room last, it is determined that each of them are to have a couch to themselves, though Estelle does not want the remaining green couch. Also rejecting Inez's offer of her red couch, Estelle decides that only Garcin's blue couch will do, as it matches her dress. Garcin responds to this with complete ambivalence, setting the stage for clashing personalities and reinforcing the idea of the play that "Hell is other people."
Perhaps the colors of the couches are meant to be significant, but it is hard to know definitively. However, considering the furnishings is a sound analytical move.
Because the room is one...
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