Thanks for shaving these photographs.  I always thought that the rough surface on the back of early US SF Grp DUIs was an indicator of a reproduction.  Below are photos of genuine and reproduction early 10th SF Grp DUIs and 77th SF Grp DUIs.  The ones with the rear rough surfaces are reproductions.  However since you got this 300th SF Det DUI from the veteran himself and I have not come across any other variant over probably a 30 plus year search it must be the real McCoy.     

I recently picked up this ww2 pin that I believe is a rare Early Ww2 Aerial Gunner pin. Any information on it and when and why it was awarded is appreciated. 

Just snagged this on eBay missed his squadron one patch and his PI belt buckle . But happy to get named squadron one Vietnam uscg group and named 80s medal . no research yet . Not finding much . Any coast guard sites I could find info ?

Well, you can request the Cold War Certificate which is recognition and you should have received the National Defense Service Medal which is also recognition for your service outside of the war zone. As you know, the military moves slow, but recognition was and is available.   Scott

Interesting that he was in 3 different units in one month. Is that possible?

I'm new to the site. I'M appalled at the slow recognition of the cold war vet. WE trained and trained others for the eventually of a war that never occurred. We were injured and poisoned in the line of duty. Do we have to wait for 50 years to receive recognition??? I was in Germany when we went to Grenada.  I was a Drill Sergeant during JUST CAUSE and thec1st Gulf War. It's not my fault I didn't go to war. I trained the one who eventually did go and fight. WE SHOULD BE RECOGNIZED FOR ALL THAT HAS OCCURRED 

1st Lieutenant Oct 1943 "A" Btry, 1stbn, 12thmar, 3dmardiv, Fmf, in the Field   1st Lieutenant Jul 1944 Barracks Detachment, Marine Barracks, Puget Sound Navy Yard, Bremerton, Wash   1st Lieutenant Jan 1945 Headquarters Conpany, Provisional Force Signal Battalion, Fleet Marine Force, Pacific, C/O Fleet Post Office, San Francisco, California   1st Lieutenant Jan 1945 4th Bn, 10th Mar, 2d Mar Div, Fmf, in the Field   1st Lieutenant Jan 1945 Btry "L", 105mm How, 4thbn, 12thmar, 3dmardiv, Fmf, in the Field  

This was the insignia after 1955. The previous insignia is this one 

NM

Looks like early use of the M1903A3 rifle.  You can see the flat stamped bands and the 2 piece bands near the front sights. Handguards are too long for the M1903 rear sight. cool pix.