Dave, is this Amati made of Ebonite or Ebony? If wood, I 'd have a very close look at it for any cracking, especially around the tone holes of the top joint. Also the serial number seems low indicating a 1950/60 s model.

AMATI ACL 311 Clarinet & Case ~ Kraslice Czechoslovakia ~ Used In A School. IT HAS MATCHING SERIAL NUMBERS, #901158 PROBABLY MADE IN THE. Obrazec zapolneniya zhurnala ucheta raboti baktericidnoj lampi.

That would mean that it was made during the communist period. Amati was not of the same quality then as it is now. I think that, depending on if you can find a skilled woodwind repair person who could get it back into good working order, it would make a good 'knock-about ' instrument. * Your photos make this clarinet look like it 's made of Bakelite.