Honorary membership in BGLOs different from regular?

[Jen]

I'm reading Lawrence Ross Jr's book "The Divine Nine: The History of African American Fraternities and Sororities" and a Sigma Gamma Rho in the book mentions joining as an honorary member and later pledging.

Is there a difference in the rights/experience of an honorary member vs a "regular" member? Do honorary members have a chapter?

I'm just trying to understand why this honorary member later pledged and there was no explanation in the book.

(And if any of this is private info and can't be answered, I understand)