This is tough, because Mt. Bell is probably no longer around. So there is no one specific to ask. I would suggest you find out who the successor company is and go through them. In those years, there were no 401k plans. So the only thing you likely had as a benefit was a pension plan. It should be pretty easy to find out if one existed and whether you were entitled to it. Since you changed jobs in that time period, it is probably there was no portability. Depending on the vesting schedule, you may have missed out. But it is worth asking.
You might be able to find information out about the company from Free ERISA. But you might need someone to help interpret the information for you.
Hope you find some good news.