i have a reher morison 509 that from new has no guide seals and the tops of the pistons had oil on them during dissasembly and some on the intake valves that were in the closed position. they must have there reason. the machine shop local to me said to put seals on all valve to keep oil out of the combustion chamber as it could cause early detonation. i also have a scott schafferof 565 and fron new has the seals with triple springs. figure that one out. two well know engine builders with two different ideas and reasons, good luck