Do I have to pay taxes on the gross proceeds for non-covered securities?

[MichaelL1]

Yes, unless you enter the cost (or basis) of the stock sold in TurboTax.  

Many times you can go to prior statements or do some research on the internet to find the cost basis of when you acquired the stock. 

"meaning that brokers may not provide detailed cost basis reporting to the IRS on the sales of "non-covered" securities."