Your initial cost basis in the employee stock is how much you paid plus the amount of discount you received. Then, you used dividends to purchase more shares- regular shares. The basis of those shares equals the dividend paid.
It will be a long term gain. They are noncovered because the broker has no idea what your cost basis is after this many years.
If you don't know which shares you are selling, you will use the first stocks purchased, first stocks sold method or FIFO (first in, first out).
If you need to lookup historical prices, this site may help.
See About Publication 550, Investment Income and Expenses
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