I have found using Seam Grip works well for things like that. A lot depends on how much of a repair you have to make. Do you have a few pin holes, or do you need to reglue one of the side seams?

Unfortunately, an unprefixed # on a later contract medal cannot be looked up.  Only the first issue medals with an “No.”prefix  can be researched.  

Shop around.  You can do MUCH better for a patch like this.  Standard US-made 101st patches are not at all scarce.  Just almost always overpriced.   

Is this an original South Vietnam patch or repro? 

I'm I missing something here. The seller states in the description that the leather handle has been replaced and varnished and that the blade has been sharpened and repark'd. He also mentions that he replaced the webbing on the scabbard. A quick search of the sellers' other items shows replacement webbing, and straps to restore fiber scabbards. It still sells for nearly $1,400.00. Amazing. https://www.ebay.com/itm/206254958060?_skw=us+m3+knife&itmmeta=01KR6211AAWPTY8GVR3EE8BZ6T&hash=item3005c0e5ec:g:FZEAAeSwZoxp-h5e&itmprp=enc%3AAQALAAAA0GfYFPkwiKCW4ZNSs2u11xB0dCwpxRRxpeq2FKl%2Bww%2FGwsQ2G6cbO76GSoIQclY%2F1irWyoIh5efqaGRKQ9nghjThdKTNU%2FZ4uETXRsh8bQgpN0IXKlqDFZsH14dwNnvW9ouvNA3fHaty7Ah9Za80Pv3Fy5sj%2ByMgVidulRA%2BzvWkQyvpmCEJNMs%2F6ySSEYBoY7Lf0Ar1JdKEWChLQIoN7r8G2G6WbphBdIm3CiLm981RVrO1B1gTmbV2iTPYvepyEwN%2Brl%2Fe1qO7lQwm6C%2Btmnk%3D|tkp%3ABk9SR86VhMLBZw Ken

Thanks 

I'm glad the corduroy uniform was in good enough condition to preserve. It is a fairly rare custom option. Though, corduroy is a common misidentification. The fabric is really bedford cord, which is similar but harder wearing.

I found this information sheet online showing a BA-42

Top right corner: We see names like J. Howard (James Howard, the only AVG pilot to receive the Medal of Honor).    The left side (above the wing): Where names like Duke Hedman (the first "Ace" of the AVG) are found.    The lower part (under the name Bus Keeton): There are names like C. Older (Charles Older, who later became a famous judge in the USA) or P.J. Greene.    Claire L. Chennault: Located at the top center. This is the most important signature, that of the general who created and commanded the Flying Tigers.    Fritz Wolf: Signature located to the left of the tiger. He was an "Ace" of the 3rd Squadron ("Hell's Angels") with several aerial victories to his credit.    C.H. "Bud" Laughlin: Located towards the bottom left. Pilot of the 2nd Squadron, he remained famous for his exploits over Burma and China.    "Pappy" Boyington: We can see a signature that appears to be that of Gregory Boyington at the top right. Although he is best known for the Black Sheep squadron later in the war, he began his combat career with the AVG.    R.T. Smith (Robert T. Smith): Often present on these banners, his signature is generally found near those of the other pilots of the 3rd Squadron

If I had to guess I'd say the ring is possibly from the WWI time period and this type of dark green turquoise looks to me like green Cerrillos turquoise.  Green Cerrillos turquoise comes from the Cerrillos Hills Mining District, located in north-central New Mexico, USA. This prehistoric mining area sits in Santa Fe County, approximately 10 to 20 miles southwest of Santa Fe and north of Albuquerque.  The stamped silver work is indicative of the Navajo Indians.