Wishful thinking, I presume. I've never heard of a 70mm print of Empire out there. And if a print of the opening-day cut were to surface, odds are that it would be severely faded.
(The collectible film cells came from a print that wasn't faded, or at least not *as* faded, but it also wasn't the "opening day" version - I've seen at least one on eBay that clearly showed the Falcon's dish in frame when Luke falls off the weathervane.)