No. Mixers (like the MixPre and the Shure FP33) that have only one input level control are essentially controlling only input gain, and have a default "unity" pass-through to the main output. Mixers that have input trim and level control are splitting the function, offering control both of the pre-amp's input gain and the input's level to the master output.
And you wouldn't necessarily need a mixer for the 788t. You'd be recording up to 8 individual sources and could mix them down in post.
And you wouldn't necessarily need a mixer for the 788t. You'd be recording up to 8 individual sources and could mix them down in post.