I have a '57 F-20 and had a '69 F-20 for a short time. The '57 was noticeably louder when played side by side. Not sure how to describe tone really, the '57 has a nice bell-like tone, a surprisingly big sound for a small guitar. I'd say the mahogany b&s '69 sounded more as you'd expect for a guitar of its size, in volume similar to the GAD M20 or M120 (which I've also owned). Nice in its own right, but quite a difference in the sound compared to the maple b&s version. I liked the neck better on the '69 but ended up trading it.
I have that '56 F-20 with the DeArmond, and it is surprisingly loud for its size. I would say that that it's at least as loud as my '73 F-30, but with a brighter, clearer voice. I have never played a mahogany F-20 for comparison (except once at Buffalo Bros. I played a GAD version).