That would seem logical......but Oregon does not sell a 3/8-LP rim. They sold a nine spline 3/8-LP six pin rim at one time. These (and the .325-7 and 1/4-9 nine spline rims) were for the proprietary nine spline drums sold for the Poulan XXV series and a few other saws.
The only other floating 3/8-LP rims that I know of are those sold by Stihl for their proprietary 'mini' seven spline drums...