Recently, we have Parker and before that, Emerson, declaring an individual right. That's two lower federal circuit court cases favoring the individual rights interpretation (Emerson is weak in that it overturned no federal law, but I'll still include it).
Those 2 vs. maybe 40 other lower federal circuit court cases declaring a collective right. The U.S. Supreme Court will be examining those lower court decisions when they go about their interpretation of the second amendment.
You say there's an earlier legal record of individual right interpretations? By federal circuit courts? I know of none. Zero. Zilch.
But if you have some, I would be interested in reading them and will certainly correct my statement.
"Even a great many liberal constitutional academics agree."
Well, color me unimpressed. Academics also believe man causes global warming. And 5,000 people are members of the Flat Earth Society.
They're out there--just pre-1900. I dont' have time to indulge in a "Google episode", but as I recall, Stephen Halbrook has an online copy of a brief that he did for one of the federal courts which cites quite a few.