I’m going to miss you my friend.

All are WW2 M1937s. The gun metal emblem, first in the picture is circa Korean war era. 

Basic un-named Naval Aviators buckle. Listed as: Vintage Cavite Phillipines Navy Pilot Trench Art Buckle Signed and Personalized, $164.95.           

German Luftwaffe boots knives. Lufty  “Stick 5’s” with sweetheart grips, possibly from an aircraft canopy. I’ve only seen a few of these in the past. I picked one one a few years back. There cool! Stick Lufty’s are real fighting knives, they weren’t made for dress uniforms. 

Recent sold buckles:   SLMO CO URL , Seller had it listed as: Vintage US Navy Commanding Officer CO. No idea what it stands for but at $22, fairly decent price.    A good Sam Miguel oval for $29.99  

There is definitely value to what you got. Don't know what you paid for the lot, but taking the price you paid (buckles, sellers premium, tax and shipping) and dividing it by 9, that'll give you a baseline as to the value invested into each buckle. There is definite room to spin these off, which is what most of do to re-coup. You can check ebay to see what the comparable buckles are going for and set your values from there. From a simpleton's point of view, once you make your nut (invested $) then everything else is gravy. 

Don't forget those at home awaiting their return . . .  

Not entirely sure, but in the early 60's to 80's, microwave transmission systems were known as "long-lines". The US military used them on a smaller scale and in Vietnam. The 1st Signal was a MASSIVE organization (encompassing more personnel and support troops than a "heavy division"). Below is a link to the subject, and note one of the units on the map, stationed in Saigon. I believe LLD#4 may refer to "Long-Lines Detachment #4" (While the HQ was in Saigon with MACV, there would've been detachments at or to service the receiving locations)   https://armyhistory.org/1st-signal-brigade-2/

Hi to all,   I’d like to have some informations about these marking (stenciled) on the rim of a US M17 helmet. Sc 162 I bought this 314 th field signal battalion helmet two weeks ago. It’s in pretty good condition with a perfect chinstrap.   I’ve already noticed that sometimes on the helmets of the 89th US ID we can find two letters and two or three numbers (stenciled or not). Could this mean anything ?   If you have an idea, just let me know.   I put pics below (rim, side)   Have a great day   Dominique