Without a doubt there are a lot of people into the hobby of patch collecting. They go after the new designs, especially if some of their dealers have stock patches from the annual bike rallies. But many of them also like to collect vintage military patches from World War II, Korea, and 'Nam. The World War II patches might be some of the most desirable from a collector's standpoint, so if you're new to patch collecting and you plan to include World War II items, there are a couple of things you need to know.
First, embroidered patch manufacturing during that era was a lot different than it is today. The most significant difference is the edge. Modern patches are either die cut or finished on the edge; the finished edge is also known as "merrowed." But back during the war all of the edges were "cut" edges. That means embroiderers did all of their thread work on a piece of fabric first, then cut the finished product out. A cut edge is pretty easy to see with the naked eye.
Next, World War II era patches were made with cotton thread. Most of today's stock patches are made with synthetic threads because they tend to last longer and hold their color better. With a pretty inexpensive UV light you can tell the difference and threads very easily. Synthetic thread glows brightly under UV light, cotton doesn't.
When you're collecting patches remember that value is like beauty; it's in the eye of the holder. It's great to buy World War II reproductions and commemorative patches made in the modern era as long as you know what you're buying. Just don't put your hard-earned money into what you believe to be an authentic World War II item if you're not sure it is.