Yes, there is a kit for it. It is available from Briggs or you can make your own.
FWIW, You DO NOT finish ream a DU bushing. The old style steel bushings sure get finish reamed to size. The DU bushing has a coating on it and finish reaming it would destroy the coating.
We still install both these bushings here in the shop and have fixtures to make them perfectly perpendicular to the bore.
We would need your block and sidecover that you are using to install the new flywheel side main bearing (bushing.)