Interestingly, I came across this and have ordered a set to see if they will work for the headlight bezels on 1971 Cuda Grill. This is a 1971-72 Sharktooth Grill Park Lamp Hardware Set for a 340 Duster/Twister made by OER, PN# MA4743 - . Not sure of the diameter of the retainer, but worth a shot since they are Mopar, 1971 vintage, and for a grill type application (though A-Body). You would think Chrysler would reuse retainers across different platforms??
BTW, since these retainers are not supplied with the Repro 71 grills and are also not included in the grill hardware kits that different vendors sell, what do other people do?