I agree, this one looks as though it has never had a pontil applied to the base.
It may have been blown into a mould and then reintroduced into the glory hole to fire-polish the mould marks. Or it was just shaped on the blowing iron, then cracked off and the top rim was ground flat after it cooled down.
Ivo's, however, looks as though a pontil was used (so that the lip could be worked) and then, after the vase was cracked off, the pontil scar on the base was melted flat using a gas torch.