There are a lot of fake Viet Nam War patches that are for sale in markets these days, and potential buyers or collectors should be very careful. If a patch is labelled as having been made during the Viet Nam War, rare and original, then follow some tests to check first the accuracy of the listing.

1. How strong do the colours of the thread or the material look? If it is original from the war, then it is probably more than 30 plus years and everything fades. If it's a paper item, check for signs of fading as well to see the age. White paper does not remain white after 40 years, no matter what a listing may say.
2. Check to see if similar sellers have the same item for sale, and what their starting price is.
3. The most important thing to do is to check a seller's feedback, because this will list the item which was sold. If a seller says he has a "rare in-country made" patch, and he's sold ten of the same item in the last two months, you can be sure he is selling fakes.
4. The other way to find out is to ask the seller directly. Maybe he picked up the patch at a deceased estate, it does happen. But again, if he has sold the same item more than ten times, you'll know for sure to avoid a sale.

I've been to Viet Nam twice now, and the military markets there are amazing if you're a collector, but you still need to be discerning as far as the originality of some items are concerned. The war has been over for a long time, and a lot of buyers have already been and gone through those markets.

The patches for example, there are sellers in the US who buy 20 of the same item from the military market for between USD $3 and $5. Some people in VN sell directly to the sellers in other countries. When I was there, about three or four large plastic bags were brought out all full of patches, all fake, for me to have a look through. Having seen what I've seen, I honestly believe a lot of those patches have made into the E-bay market unfortunately.

So, the old saying "buyer beware" rings true once again in the ears of potential buyers.