Yes are entitled to overtime pay for all hours worked over 40 in a workweek in the last 6 years. In addition to the unpaid overtime, you and your co-workers would be entitled to recover penalties which will double the amount owed to you. For example, if you are owed a total of $20,000 in unpaid overtime, you would be entitled to a total of $40,000 under the NY Labor Code and Fair Labor Standards Act. Sounds like you have a good case.