In regards to other people wearing the "Eagle Globe & Anchor. In my opinion, other than Corpsmen, the unit I feel that "may" have been able to rate the "Eagle Globe & Anchor" are the Seabee battalions assigned "directly" to Marine Corps Engineer regiments (17th,18th,19th & 20th) during WW2. After Navy boot, these men were issued Marine uniforms, trained with Marines, and subject to Marine Corps rules and regulations, being directly absorbed into the Engineer Regiments. They were integral parts of the Marine assault shore-party landing and fighting operations in the Pacific. As one WW2 Marine told me.
"I fought side by side with the Seabees on Iwo Jima. I was with the 4th Eng. Bn. as a Demolition Marine. The CBs were always there when you needed them They were not like Marines, "(THEY WERE MARINES)"
Unfortunately, this is a moot point, as most of them are long gone now.
Semper Seabees
Son of a deceased WW2 Seabee