I would be most grateful if anyone has information on the existence of this record or confirmation that my theory of the non-existence of SLP 901 because it was released instead as SLP 501.
I'm not sure that this is the same Spectrum label. Different standpoint, different producer (that is key!) and different Catalogue number prefix & series.
Siggy Jackson is the producer and label owner of the other label. This looks to be a religious label.