I thought the chrome trim option fit over the top of the fairing. No? I just got my SERG, still at dealer waiting for options, and this was ordered too. But I haven't ordered the CB yet.
Let me preface this by saying that I have not tried to install the windshield trim on a 2009 SERG. I think I understand why it won't fit, though.
The rubber windshield seal for the stock SERG windshield sits between the windshield and the fairing, i.e., the windshield mounting screws go through the windshield
and the rubber sealb. The stock windshield has the mounting holes indented (frenched in?) and the material thickens around the screw holes (to help prevent cracking?). The rubber seal has hole larger enough to allow the raised around around the screw hole on the back of the winshield to sit down into the seal.
Stock Road Glide windshields -- and any windshield that assumes the stock seal such as the KW -- has the screw holes flush with the windshield surface. When you try to mount this type of windshield using the 09 SERG seal, the screws aren't long enough. So, you have to mount the windshield without the stock seal giving up the good seal that it create as well as having minimal protection for the painted fairing surface beneath the windwhield.
The CB windshield for the FLTRSE3 has been designed to mount using the stock rubber mounts. I don't know if the screw holes in the windshield are flush or indented. If they are flush, then CB must be providing longer screws to mount with the stock hardware.
I think that others have mentioned here that hte CB windwhield comes with a set of new mounting hardware, but uses the stock seal. I am still waiting on my CB, so I don't know what is included in that hardware. Perhaps someone who has their CB shield can chime in here.
So, this is why windshields that assume the stock (non-CVO) Road Glide mounting hardware and seal don't fit so well on the SERG3. Some have also said that there is a slight difference in the shape of the fairing where the windshield mounts, but I have not yet been able to verify that.