The Company of Military Historians describes their uniform as being standard US cavalry, with the exception that they only had one lace and button on the collar. The troopers wore a crossed saber badge on the crown of their kepi and the officers wore a smaller version of the crossed sabers badge on the front of their kepi.
This may help, and will also show their kepi.
http://www.rushslancers.com/
If this isn't the detail you're looking for let me know and I'll dig a little further.
Terry