Well, I still read Marx's main line of thinking as associating "abstract"
labor with commodity production, though Allin's citation raises
difficulties for this interpretation. Perhaps some of the other OPE-Lers
can shed some light on this.
There's no doubt that labor (in the sense of human productive activity)
predates commodity production and capital. The question is in what sense
(if any) it becomes "abstract" before commodity production.
Yours,
Duncan