Wow. I'm pretty sure that is the same vintage as my first Silvertone Bass amp I owned when I was 15. ( 1968 ) mine was a 75? Watt with a 15" . Anyhow, it was a turd. I quickly replaced it with a 66? Bassman with a 2x 12" cab. I remember that the Silvertone was more powerful but the Bassman at 40 watts was way louder.
I also remember the Silvertone was transistor and it was a bit distorted in a bad way. We ended up using it as a guitar amp because we didn't notice the distortion as much as with the bass.
I traded it for a Vox Wha Wha I think.
I was young, but even back then we new about tube amps being way better than transistors. I don't think I've ever owned another transistor guitar amp since.
This is the closest picture to what mine looked like but I think this is a guitar amp. I can't seem to find picture of mine, I'm sure had only a few knobs. But the Tolex was this color, and the logo and faceplate looks right.