I had the same problem and got some good advice on the SDC website. First of all, although the parts book shows them as separate parts, the aftermarket replacements had the cork oil seal already installed in the 193049 housing. These are routinely offered for sale on ebay for between $50-80 a pair. I don't see how you could get that cork ring into the housing without breaking it anyway.
But I also got other advice. It turns out that the felt crankshaft oil seal from the timing gear cover of a Champion 6 is the right size and with care, can be stuffed into that groove. I don't have access to my parts book at the moment, but perhaps someone else can jump in here with the part number.
Word of advice: if you choose to buy the completely assembled aftermarket cork oil seals, soak each one over night in water, then very gently install it on the axle and let it dry out there. 60-year old cork is very brittle.