According to Guitar Player magazine, all of these answers are true. Jimi played RH guitars strung LH, he played LH guitars, and he played RH guitars strung RH. They quoted Pete Townshend, who said Jimi borrowed his RH guitar once for a show. He destroyed it, after destroying the audience.
Fender’s custom shop has a Stevie Ray Vaughn signature model of the Strat. It has a lefty tremolo bar, which SRV used so that he could sound more like Jimi.