Around here where it gets to be -40 a blind eye is turned to what we are wearing as long as the UPS brown and logo are front and center. Staying warm is the main thing. It's tough to find a brown turtle neck, so I wear a beige one. Yes i could wear white, but I have issues with that.
"Trust me - the bomber jacket included with the wind breaker/rain coat outer is PLENTY warm enough with just a t-shirt on under it."
Maybe where your are but not around here. I wear a turtle neck, UPS long sleeve shirt, a fleece, the UPS vest, and the UPS Jacket. That keeps my torso warm. My legs are covered by UPS pants and under them a pair of fleece long johns. My feet have a pair of -40 boots and depending on how cold it is one or two pairs of -30 socks on them. My hands, well thats a problem. I have a pair of 100 gram thinsulate gloves over top of glove liners and on the really cold days those hand warmer things are in there as well. On the head is a brown, non UPS issued toque.