No, you only need to enter your T5008 once in TurboTax. You can enter them either on the T5008 slip screen (which is where they will be if you import your tax information using AutoFill) or in the Capital Gains and Capital Gains Deduction Profile.
You can choose either method of entry, some people prefer to use the Capital Gains Deduction Profile as you can enter more details on your dispositions here. But do not make the mistake of entering these amounts in both places as you will reporting them twice.