Cant say wether Im still in GA or not. The Co I fly for is more like a John Shonky Aero Club Pty Ltd but with 737s on the line. But the subject is uniforms.
Airline Co dressing is more to tell fellow employees who you are. In big companies no one knows everybody else so if an engineer is looking for a captain to yell at he will look for a dude with 4 bars. If the traffic staff are looking in the terminal for the captain he'll stick out in the crowd like dogs balls. So thats what I wear because the my boss wants it. Personally Id rather wear jeans and a Fly United Tshirt with the 2 ducks on it.
In my time in what is called GA I wore the stock standard kaki. This is because the boss told me to wear it. Later when I progresed to heavier metal the boss wanted me in black shoes business shirt and slacks. Ties off on a hot day. No wings, epalettes or any of that !!!!!. So thats what I wore because the boss wanted it.
So its up to the employer as to what you wear.