Very similar to mine. I got mine off E-Bay also but they came directly from Speciality Spares. I think they have an E-Bay site. They are loud so don't get them if you want something tamer. On long rides I usually wear ear plugs. They do bolt right up with the adapter pipe. Also if you have a center stand you'll need to make a stop for it. They are loud and I love them. Here's mine.
Here's how mine looked out of the box.
Here's after I drilled out the ends to make them a bit louder and totally free flowing.
I would ask the seller what the inlet diameter is. The Bonneville's header pipe and the adapter pipe are 1.5" or 38.1 mm. Just about anything could be made to work, but the ones I got and I believe the first ones you show are a direct bolt on and go. Others may need a longer or shorter support bracket that attaches to the rear footrest bolt.
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