I could be wrong but I thought some cars had press in and others thread in? Anyway, just checking Rare Parts they have upper and lower thread in and upper press in.
If you are talking about an option to purchase at Rare Parts web site it is there but requires several clicks to get there. Give them a call and they will walk you through it and to the part description with pictures. Amazon also sells Rare Parts.
You can find ball joints at various suppliers, some good and other not so much I imagine.
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