There are a few period pics out there that show surgeons in a several different of trouser types. I have seen dark blue w/ gold and plain dark blue. These make up the vast majority of trousers seen. I have seen about half a dozen pics of sky blue trousers and all are plain except 1 pair that appeared to have the Confederate regulation braid on them. Most of the sky blue pics were later ('63 on) war. As the war progressed you started seeing plain trousers, dark and sky blue, sack coats and shell jackets as function overcame form in the field.
your obedient servant,
Surgeon, 2nd Brigade
"not really a surgeon, but I did stay at a Holiday Inn Express"