Any releases of Empire and Jedi prior to 1993 would be theatrical audio, and video too, if it's letterboxed. Every home video release of Star Wars has had the altered 1981 opening (where the movie is given an episode number and named "A New Hope"), except the 2006 DVD bonus disc, which is the only one with the 1977 theatrical opening where the name of the movie is simply Star Wars with no episode number, just like it was in theatres.

How much the revised Star Wars opening matters to you is up to you (in spite of simply being the addition of some new text, they managed to screw up the edit even then if you watch carefully), but you said you wanted theatrical, and, well, that's a complicated story. And that's not mentioning the fact that when you saw it in the theatre in 77, chances are you didn't hear the stereo mix which is the only audio mix you have the option of buying officially. If you want the original mono mix or the six-channel mix, your only option is fan preservations.

Also keep in mind, the home video releases have been through processes that prevent them from looking or sounding quite like the theatre. At best, they're considerably brighter, less saturated, pink-shifted, and they have compressed audio dynamics. This makes things like the matte boxes around spaceships a lot more visible than they'd have been in the theatre. So I can't stress enough--fan preservations are a better representation of what it actually looked and sounded like in theatres than anything you can buy.