Source for Sheridan seal kits?

Hello,
I’m trying to rebuild a Racine WI era Sheridan/PMI 1 df paintball marker. It is powered by 12 gram cartridges, and uses many of the same parts as Sheridan traditional air guns.
Is there a source for these parts; new or reproduction? I’m particularly interested in exhaust valve pin/seal assemblies and co2 chamber face seals.
Thank you.

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