Let me see if I can link what I have available for Saito. Unfortunately it doesn't go far back in history, and is more likely a not too recent catalog and also a boiler operation instruction sheet. Perhaps you already have both.
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Hope those are of some interest.
I too would like to find info on older Saito offerings as I do have several here also. I would think that Miles (Logoman) of fair fame on the old forum would be a go to source for such material, but alas he has seemingly dropped below the horizon and been unseen for quite some time now.