There's four way's it's been played...
The open E way on the single, and I think at the NME poll winners concert in 1968.
The r&r circus way which is in standard tuning, but he plays the main riff using the lower notes than later versions, kind of like the closest you could get to the original, but in standard tuning.
The ya ya's way, standard tuning again, but played higher up the fret board. Then finally in open G with the capo at the 4th fret.
All have slightly different feels to them. I still prefer the original single release way.