You mean a Marine prior service? That is news to me. Came across this:
"For one to wear a Marine patch you had to be in the Army during the authorized period with a memo stating that in your records. In addition, coming from the Marine Corps to the Army with a 'Combat Action Ribbon' does not mean you can wear a CIB as some idiot started that rumor years ago. I know this will also cause heart burn for some soldiers, but the color version of the Big Red One is unauthorized and has been addressed by the uniform board years ago yet it still is being done."
"Soldiers who are authorized to continue wearing a Marine patch as their combat patch include those who served with Marine Corps units during operations that qualify for an Army combat patch, as prescribed in Army Regulation 670-1, and who have written approval from the Army chief of personnel or a delegated representative."
"However, under a policy change that took effect June 11, soldiers in Army units at the company level and higher who are attached to, or under the operational control of, deployed Marine units no longer are eligible for the policy exemption that allows them to wear Marine logo patches as combat patches."
I believe the same reasoning behind not letting Marines wear the Ranger tab who completed the school. I believe the requirement is designed to preserve the heritage of Army units. You can't wear a CIB in a Marine uniform.
