Yep, turbulence penetration speed is a target air speed for turbulence penetration. It gives adequate margin above the stall and below any limiting speeds assuming you're not flying too high for the conditions encountered. The type I fly allows for lower rough air speeds at low level to facilitate climb through the turbulent layer, but in general you should aim for the published RA speed.
Something else that people tend to forget is that it is a speed for severe turbulence. In your case you don't need to fly at M0.78 just because you've had to put the seat belt signs on. On the other hand you don't want to be caught out either. Personally I'd not worry about the speed for light turbulence, and I'd go for RA speed for moderate turbulence in case it becomes severe and of course try to find a better level and/or try to get out of the CB I'd blundered into
.