Is your current fuel pump vacuum or mechanical? An 854 should have a vacuum pump, but it could have been changed over the years.
Either way, the OEM Kohler kits are all NLA. You can buy a new mechanical pump from Kohler, but they are black plastic and don't have provisions for the threaded fittings/hard line like on the old engines. They are also close to $70!
231597-S is the number for the old kit to repair the vacuum pump. You might be able to hit up some old Kohler dealers and find one in a dusty box on the back of their shelf. If not, keep checking ebay for a used aluminum fuel pump. Your cam IS equipped with a lobe, so you can install a mechanical pump if you have to.