https://archive.org/details/cassellsdictiona00gree/page/884/mode/2up I've seen several sources pointing to this particular dictionary, but I'm not familiar enough with Internet archive lending to pull the specific page. I also haven't found any primary sources from that time period to correlate.
Its much more recent, but 50 Cent used it in a number of songs, including 2005's "in my hood"
Sheeit, bitch get out of pocket, she need some discipline
If you look at the 50 Cent lyrics in context, they're saying that crack money has slowed down, so the "bitch" is paying out of pocket. https://genius.com/50-cent-in-my-hood-lyrics
Crack money slow so you know niggas is trippin' (Yea!)
Shorty down there on that Queens tracks takin a whippin'
Sheeit, bitch get out of pocket, she need some discipline
Peep the fiend shootin diesel in his arm in the alley
Edit: on reflection, I'm not sure I understand the lyrics well enough to say which way he means "out of pocket" to be taken.
In what of part of the English speaking world is this phrase used this way. I've only ever understood "out of pocket" to mean, to use immediately available resources to pay for something.