Burr refers to the cap of the rivet. The Originals attaches a burr with YKK markings. 

The brand logo is stamped one by one, by hand, by me. 

The bottom part of the Burr is referred as the rivet. The Originals will be using the rivet to the left, produced by YKK. The quality is great, but has a 'new' quality to it, which may affect the vintage feel of your jeans. 

You can have the option of using the rivet to the right, an American made rivet with a rough feeling to the finish. I recommend it to bring out the true vintage qualities. 

The left is YKK and the right is American.
There is a difference in the sense of material. The YKK rivet is thick. 

When fabric protrudes from the between the bar and the rivet you can tell that it is handmade. It's a specification that can be noticed in true vintage denim. Both are finished with a hammer to round the sharp edges of the rivet.