I think I may have the information you need. AMSafe (
http://www.amsafe.com/products/detail.p ... categories ) makes a product that appears to look very much like our part -and surprise, surprise, they are located in Elkhart! The link provides a phone number & names to talk with. The part number you seek
could be #10020 or #1-1053-02 or some portion of the assemply.
LaVanture is supposedly a supplier of the seat belt, but I wouldn't worry about contacting them because they have the same or nearly the same address as AMSafe and may merely be a distributor.
I will go out & look at mine tomorrow to see if I'm on the right track.