Generally, you don't have to degas. That is usually done in kit wines, to make them ready to bottle early.
If you have the wine at a cool temperature, though, it may hold on to some co2 and actually appear carbonated. That happens because cold solutions allow co2 to more easily dissolve into the solution, and the fermentation has slowed down enough where there isn't enough pressure to "burp" the airlock and let the co2 out.
I've only had to degas one wine, other than kit wines, so it's definitely not commonly done!