When Gus leaves his apartment to go join Mickey at the party, he sets down his bass guitar and leaves it in his apartment. Later, when he picks up a bass at the house party, it is the same bass guitar as seen previously in his apartment. You can tell this is the same guitar (and not just the same model) from the unique sticker on the fretboard at the 12th fret.
When Frank comes into the room and grabs a beer he twists it open. The beer was Red Stripe and Red Stripe is a pry open top.
In 1.2 One Long Day Gus throws all his Blu Rays out the car window, including a leather case which is briefly shown lying in the street. At the beginning of 1.4 Party in the Hills, when choosing a movie to watch, Gus selects Perfect Storm out of that same leather case he had tossed away two days earlier.