There are a few parts they figure would be so unneeded for service in the future, they never put them into the parts system or the catalogue. This part looks like its one of them.
A few others people don't realize, some of the foot pedals, like the brake and clutch do NOT have any replacements neither from the Dealer or aftermarket on a lot of vehicles.
Seats can be purchased through the dealer and they are often special order and costs near $1000 or more.
If one person out of 100,000 units made needs the part, its just not worth the cost of stocking it in the parts system. So if it needs replaced, you're going to have to go to a junkyard and salvage it off another vehicle.