I was recently wondering how this surface was created/carved? It looks like a mark that a wood carving tool would leave, but surely carving each individual line wouldn't result in such a uniform look?
I think there are potters good enough to do that: there's one in my class who does very neat, tidy, and symmetrical fluting, (he's very experienced and only there to use the facilities, not learning as such, if you can ever say that).
Either freehand with a loop tool or using a gauge rod and a stop on the tool, final trimming when leather hard will produce the effect near the rim.
Another leftie here, but I'm a bit of a mixture, whilst I'm not particularly ambidextrous I do do some things equally well or even better right handed; throwing a ball is one I can think of - I just can't really do that well left handed.
I can't write or use cutlery right handed, most of my carpentry work is done left handed, I can't use a hammer or saw right handed but planes or chisels are fine either way.
I learnt to throw pots right handed (anticlockwise wheel head) cos the wheels I learnt on weren't reversible - mine is, but I've not tried it lefty fashion yet, I will one day, if only to say I've tried.