Sounds like a Hohner Pokerwork, so I doubt it will be worth too much as a collector's item. They are pretty tough, however, so probably plays OK. The main question is whether it is made in Germany or not. Like all mass produced items, they ended up being made (or at least assembled) in cheaper labour countries. But that didn't start till the late 80s, I think, so probably OK on that front as well. The key or keys (if 2-row) it plays in can also affect the level of interest. D/G are common for Morris and barn dance/ceilidh band use, while C/F is usually better for singing, and could therefore attract more interest if the tone is good.