I think we know because an atomic bomb prototype would have been far too large and conspicuous for an individual to take to, let alone leave at, a bar :)
Re:Apple iCloud Experiencing Issues
by Apocryphon on Thursday July 04, 2019 @06:10PM
(#20358202)
Not to mention the bar would’ve been in Los Alamos, a town run by the military.
Also the iPhone leaked was an iterative-model not the original.