I compared the measurements of a set of unused swingarm bushings I bought from Doug at Moto Carrera with this set on E-bay.  My set has different dimensions.  Measurements for mine are:
- Length 40mm
- Thickness 28mm
- Flange width 34mm
- Inside diameter 22mm
Conclusion - the E-bay bushings are not for RD350 / RD400 unless the bushings I received from Doug are not sized properly, which seems unlikely.
https://www.ebay.com/itm/JAPAN-BRASS-SWING-ARM-BUSHING-SET-YAMAHA-RD350-RD400-I-THINK-SEE-PICS/372607886938