Its a real tough call.

Strictly speaking I would say no, its a claim on BTC - but the same goes for LN

In both cases, the "BTC" has been locked in a multisig and you are using an facsimile representation of that.

(Side track: But I think the fears of Liquid Federation not allowing Peg-Out are reasonable but overblown...as I can think of ways to bypass their ability to do that... remember that Liquid is Confidential Transactions by default so no one can tell what you're holding or what your transferring....even more, if they prevent direct peg-out you could always just transfer the L-BTC to an exchange and sell it for BTC....)