Not if its represented as a celestial birth sign, signifying the month that the PC was born, and supposedly affecting their personality, aptitudes, and or abilities as a result.
bethesda can change stuff if they want
signs werent that big of a game changer in the first place
'yay im born under the serpent, now i can poison one thing every 24 hours'
guess they just figured ppl would want to change them around after a while, since its not like any of the signs granted uber spells or anything