In rebuilding my 636S, I came across a variation in the Check Assembly - Discharge Disc (item 30) in the photos. I looked at the interchange table that is posted but saw no differences across the board. While the old (item 30) 'disc' I removed was another check ball design like the Intake Check in the same circuit (item 29), the part that came in my Walck's kit appears to be a different construction - more of an actual disc with a retainer wire! The nomenclature does say 'disc' so maybe the replacement part from the kit is more accurate than the old part I pulled out? Thanks in advance for any ideas here.