Susan, I see nothing about the song which could be classified as abolitionist: the attitude expressed toward the working class in the third verse is highly elitist--the clock is compared with the run of workers:

My grandfather said that of those he could hire,
Not a servant so faithful he found,
For it wasted no time and it had but one desire,
At the close of each week to be wound.
And it kept in its place, not a frown upon its face,
And its hands never hung at its side...

It is certainly assuming a working class (which the grandfather--if not Work himself--held in low esteem) and a leisure class (ol' gramps, when he was a lad, could sit and watch the "pendulum swing to and fro" for hours, we assume with his hands at his side, or idle, at any rate--and this is seen as a sign of the attachment between the boy/man and the clock and possibly of the boy's active mind, not as a sign of idleness).

--seed