heres what northgeorgiahawg wrote in another post think this is what you were looking for
You need the "Rumble" collection footboard inserts. They are no longer listed in the standard parts catalog nor online. They are CVO parts now. I just put them on my bike. PNs are 51502-09 and 51510-09. Can't remember which one's the left and which one's the right. Get ready... they are $109.09 EACH! They go in the Streamliner Passenger Footboard Kit 50378-07B, which is $379.95.
Using these means your passenger's foot comfort will set you back 6 FULL C-notes!
Here's what they look like, if you're interested in springing for them. The kit has the chrome mounts, pans, etc. The Rumble inserts are separate, and are sold each, as stated above. Obviously, I liked them enough to part with the not-insubstantial amount of cash required!
If you REALLY want to go top-of-the-line, you can get the adjustable footboard mounts like on the Ultras... those mounts are even more $$$. I am actually thinking about getting those - and if I do, I would be looking to sell the fixed footboard mounts I have now.

