I bought a Corbin Modular seat for my '11 Concours off of ebay. "Thankfully" the box was lost for over week with no scans, and then turned up.
Why do I say "thankfully"? Because I developed a little bit of a rapport with the seller during that time as we both watched the tracking number. He seems like a nice guy and just bought his Connie that came with the Corbin which he didn't like.
Well, when the seat arrived I tried to install it like I had so many other Corbin's in the past. But the seat seemed really loose? Hell, without the back portion on, there was nothing locking the front down! After reviewing the installation instructions on the Corbin website I quickly realized the problem... There is a bracket that has to be installed under the seat that locks the front seat down, and I didn't get that bracket. I emailed the seller asking if maybe it was still on his bike. Because I am incredibly inpatient I called Corbin just to see if I could buy another... The nice lady went out into the warehouse and came back on the phone about 4 minutes later and said, "Yep, we have one. It'll be $45 plus $5 to ship." So I bought it. And then the ebay seller notified me he had the bracket and would send it to me for the price of shipping.
My warning: If you are buying a used Corbin Modular seat, make sure you get the custom bracket or else you'll be spending a bit more money than you wanted!
As of last night I saw two more Corbin's on ebay. Neither had the bracket listed in the pictures.