Elko County
Some collectors pay very close attention to detail. Even though an agency patch may be the same patch, they look for slight variations in shape, color, writing, material used, etc.  Although I do pay attention to variations like this, I don't go too crazy over it.  However, If you are going to pay attention, Elko County is a good patch to use as an example. These four shoulder patches are the same style, but each is different.
Example: Look at the tools at the bottom of the star. On three patches, they are dark. On one patch, they are very light.      Etc, etc., etc.