Hi Andewt, That bottom is sometimes referred to as a "Modified Pontil" - but I have never seen that explained. 'The dot in the center is a mark created in the area of a vent hold. These vents had to be cleaned often and I think they used a pointed tool and no doubt a wire to clear the hole. RED Matthews
Andrewt, I didn't mean that it has to be a machine made bottle. One would have to see the whole bottle to tell if it was machine made. From your one picture - all I could tell you is what I saw. One would have to check the mold side seams - to see how far up they went on the bottle. The bottle could have other clue marks on it.
RED Matthews