IF they were issued insignia they would have (if done in accordance with standard practice of the time):
Crossed Swords, to represent the Cavalry.
A No. 1, to represent the Regiment.
A Letter (A to I, plus K, No Company J, as J's and I's look alike.) to represent the companies in the Regiment.

I believe there is a book written about this regiment, could look there to see if they were issued insignia.

here is a link to a web site with informatoin on the Regiment and Companies: http://ehistory.osu.edu/uscw/features/regimental/louisiana/confederate/1stLouisiana/index.cfm

JIMT