No, because you'd still need book keeping around the length of [first, last), even if the implementation does under-the-hood O(1) movement of nodes in [first, last) from other to *this. Computing the length of [first, last) is still an O(n) operation for forward iterators.

Maybe you're assuming [first, last) is the entirety of other? For that case, there are overloads for splicing an entire list in O(1) time:

    void splice( const_iterator pos, list& other );
    void splice( const_iterator pos, list&& other );