Redd was it really not a great instrument in 1952? I bet it sounded identical.
That would be my bet as well. Acoustics open up with age, and that can be a process that can take more than 20 years (most notable on the old Guilds from the 1970s, which sounded awful then but glorious now) but I've never heard it with a solidbody.
The thing which has improved more than anything since those old guitars were built are strings. If they sound better nowadays that would be why.

