If you want to split hairs, even the 4.1 isn't technically the original. Grease premiered and played exclusively with 35mm Dolby 2.0 prints for the first two months of its run. A smattering of 70mm prints showed up in late August.
Probably not. Randal Kleiser was directly responsible for that remix (done in 1998 for the film's last reissue) and unless somebody at Paramount pulls a 4.1 out of the vault, we're stuck with it.
...and even if they did, the usual faction of this forum would boycott over lack of Atmos.