What do these torsion bars belong to?

Found a pair of supposeably '69 swinger 340 torsion bars today that are marked on the ends 328 L and 368 R and cannot find out if they indeed belong to a dart. Guy swears he bought them years ago from mopar (early 70's) for a swinger 340 he had but I can't confirm this.

Again they are marked with 328 L and 368 R on the ends and they both have the DCPD logo on them too.

What do these belong too....help!