I was at Ceol Neamh Pipe Band's Burns dinner last night and I'm thinking not only is it accepted but expected that you wear highland attire. I wore a Murray ancient tartan with Black dress shirt, black tie and green hose. Many wore our band tartan but more had their own.
This was also my first Burns supper and had a great time. Go and embrace yourself in all things Scottish.
Slainte,
Mike