UDT One patch

[Tonomachi]

I purchased this patch through ebay recently and was wondering if anyone had any information on this piece. I first saw this patch on an internet insignia sales site where it had already been sold but the photograph was still being displayed which I copied for future reference. I was hoping that one of these days another one would pop up for sale. This interent site described this patch as being made circa 1940s during the occupation period in Japan. This site (http://www.ljmilitaria.com/navypatches/us_navy_ground_forces.htm) states that UDT 1 was recommissioned circa 1947 which came from a veteran. The information I have on UDT 1 was that it was one of 32 UDT Teams formed during WW2. Most of these teams were decommissioned after the war except UDT 1 through 4 with UDT 5 being formed during the Korean War. The information I found on the internet states that on February 8, 1954 UDT 1 became UDT 11 and some 30 years later UDT 11 became Seal Team 5. This particular patch has been copied and is currently being sold on ebay. There isn't a lot of information on insignia being worn by UDTs during WW2 and the Korean War. Does anyone know if this patch is authentic? This patch does not glow under a black light.

[vintageproductions]

Looks like an older Japanese machine embroidered variant.

[Tonomachi]

Looks like an older Japanese machine embroidered variant.

 

Thanks Bob for your expertise with the possible type and age of embroidery.