I think that you are going to have to buy new items from the reproduction folks.
Maybe someone can steer you to the most authentic in terms of material and quality.
I found this: http://www.mooremilitaria.com/apparel/3rd-pattern-jungle-fatigues/reproduction-3rd-pattern-poplin-jungle-fatigues-1227.html
[i]Reproduction 3rd Pattern Poplin Jungle Fatigue Coat. A Moore Militaria exclusive, and available solely through us, these exact reproductions have all of the correct features as found on originals. These include custom milled and dyed Poplin fabric, a button fly, web tape waist take up tabs, pocket drain holes, the correct inner pen pocket on chest, “V” Gusset sleeve (67 / 68), 1967 DSA tags, “Bandage” pocket, knee darts. If you would like an exact reproduction, these are for you. /i
And on the same site this less authentic reproduction: http://www.mooremilitaria.com/apparel/3rd-pattern-jungle-fatigues-r-s/reproduction-3rd-pattern-r-s-jungle-fatigues-economy-1357.html
[i]Reproduction 3rd Pattern R/S Jungle Fatigue Coat, Economy. We have decided to offer these as an “economy” option. These fatigues are mass produced by Rothco and are Vietnam styled, with slant pockets, etc. but they lack specific details such as drain holes, inner pockets, correct tags, etc. Because of their off the shelf fabric, lack of specific details and their production numbers, we can offer them at a reduced rate. Fatigues are 100% cotton ripstop and have been “pre-aged” so they appear to be faded and are lighter than their photo above. If you want an exact copy of original jungle fatigues, I would strongly recommend some of our in-house fatigues as listed above. If you need a less expensive set for airsoft, paintball, stage productions, etc. or if you need a pair outside of the size range that we make, these may be for you. They are okay for the field at most reenactments and should pass the “15 foot rule.” /i
Or, you could trust ebay: https://www.ebay.com/itm/US-Military-Issue-Army-Vietnam-Era-OD-Slant-Jungle-BDU-Fatigue-Shirt-OG107-Med-R-/202350508081?_trksid=p2349526.m4383.l4275.c1#viTabs_0