It was just a single piece of paper with the sketch on it and the signatures, unfortunately no other information. According to my file it was back in 2015. If the signatures can be correctly read then maybe it would be possible to find out more. I took a close up scan at the time of the signatures. Quick search on the internet not helped by the fact that the snow tracked version of the Jeep was known as a Penguin Jeep apparently. 

But the SSI is on the combat side... I am unsure if it was maybe different with the US Navy, but wouldn't the active SSI have to be worn on the left shoulder?

@patches, yes I am referring to patch type crests.

They are a standard vest mostly used by crewmembers in the back of cargo helicopters and planes, especially when the ramp is down. It allows them to have some freedom of movement to do their jobs and keep them safely tethered to the aircraft. Some are rigger modified with pockets for survival gear. Often, they are called a monkey harness.

Yes WW2

Your patch looks US made but embellished with the Engineer branch colors by your grandfather.

Thanks for the insight. It adds to the mystery of it. Would it be European made the thread would have been metric. And as you say that the construction is maybe pre-WW2 it makes the knife even more special to me. The area I live is directly directly under the flightpath to Germany and they still find planes in the polders here. So I think I will take it to one of the WW2 museums here...

Greeting.  Any input on history of this vest will be appreciated.

Thanks for the help Don

Do you have better pictures of the rifle?