That's an interesting story but unfortunately, or fortunately depending on your point of view, it isn't true. The first known case of court ordered indenture for life, aka slavery, occurred some time before that. And the owner was white.
"Whereas Hugh Gwyn hath . . . brought back from Maryland three servants formerly run away . . . the court doth . . . order [that] the first serve out their times with their master according to their indentures, . . . and that [the] third being a negro named John Punch shall serve his said master or his assigns for the time of his natural life here or elsewhere." - A Virginia Court Decision (1640) from Virginia Magazine of History and Biography (January 1898), vol. 5, no. 3, p. 236.
There is some dispute back and forth on that. Punch was sentenced to servitude for life for the crime of running away during his period of indentured servitude. Casor was declared slave for life, but not as punishment for any offense. Thus Casor more closely fits the definition of slave. As far as servitude as a sentence handed down for a crime, including servitude for life -- there were a large number of such up until recently, before chain gangs and prison farms fell out of fashion. We no longer sentence people to "hard labor".