Flat paint. Yes to both, but more of a dirt issue. Black doesn't help with that either, but once dirty, the gloss black is easier to clean.

One of my most memorable...non-life threatening...flight experience was in the left seat of Aluminum Overcast. Sit down, familiarize with the controls, confirm that it responds normally, look out at the left wing and "OMG I AM FLYING A B-17!" One of the two best logbook entries I have.