No... run away fast!
The 246 is a great model, but not in that condition. It sounds like a parts machine that's already been ganked! Either that or someone has taken it apart, couldn't fix it and then subsequently lost the bag of knobs. Tascam did have replacement knobs for those and other machines, but they were already out of certain types and colors five years ago at least. Even if you could find the knobs they would likely cost you more than you'd pay for that 246.
The 246 is IMO the best portastudio ever made. I still have my original I bought new when they came out in the 80's, but... wait for one in great condition. They're out there.
"If you canít make a hit record with a Tascam or a Fostex,
then youíre not going to able to do it with a Studer or Otari!" -David Mellor