I just read about this and I find it interesting. The website itself says they've stopped convalescent plasma from those who got jabbed but doesn't specifically say they've stopped from those who are not jabbed. However it does say:

he FDA allows people who have received a COVID-19 vaccine to donate dedicated COVID-19 convalescent plasma within six months of their infection of the virus, based on data that antibodies from natural infection can decline after six months however, the Red Cross has discontinued our convalescent plasma collection program.