An Over Bustle is attached up on
the outside of the skirt.
This is a French Bustle where the train is attached up underneath the skirt.
When choosing a bustle for your wedding gown consider the following. If your train is really full or has a lot of detail near the bottom of the train generally the Over Buslte will show off the train better.
If your train is plain or there is detail running the length of the train generally the French Bustle looks good.
There are always exceptions to this and when I see your dress on I can better tell and show you what would look the best. Also on some trains when there are layers of fabric and the outer one is really full sheer than I use both types of bustles. The under layer most likely a satin would go up in a french bustle and the outer full layers would go up on the outside.