Re: Marine Corps Regiments...
The US Marine Corps has had numbered regiments for quite some time, both infantry and artillery. Each has its traditions and battle honors, the latter being noted as streamers on the regimental colors. The US Marine Corps band in Washington DC also goes back to reversed colors for their uniforms, and the drum major wears a tall bearskin. Marine Corps drum majors have that as their MOS (Military Occupation Specialty) and have a school that they attend to earn the designation.
Sincerely,
G
I didn't feel qualified to speak for the other services