Not relevant. Of course you can transfer ownership of yourself. Self surrender is as much a protected right, as self ownership. The problem occurs, when one chooses to reassert ones self ownership after once surrendering it to another. This is because the restriction is not upon the slave claiming self ownership, but upon the master who chooses to enforce the slavery.
A market economy might grant the purchaser of such acquired ownership a civil award for contract violation, and could under certain circumstances go as far as laying a criminal penalty for fraud upon an individual reclaiming self ownership after once surrendering it (or selling it). But the condition of slavery can not be enforced.
I would suggest that in a libertarian society, only a fool would purchase another's self ownership, as no means would exist to collect, except by way of a continual voluntary transfer on the part of the surrenderer.
Saying one can not own, that which they cannot transfer, is like saying one cannot own their imagination, which they cannot transfer in full. Only the state can legally lay claims to such immoral and impossible ownership.
It is that kind of state that needs to pass into history.