I would think the body of the jug has been mould blown, then a blob of hot glass put on the base (after removal from the mould) so the pontil iron can be attached, so the body can be heated at the Glory hole and it can have the handles and frilly bits of hot glass added.
The scar has come from breaking this off at the blob of glass - hence the moulded bottom, with a pontil scar finished off as best it could be.