Responsibility of a Barista at a New Job?

So I've been in a transition of sorts, leaving a job because I got offered another job, then that job not being able to give me any hours. I started applying anywhere I'd be willing to work, which in Lincoln means any coffee shop. They tend to be easy-going, but manage to keep me busy.

I got a job at a new place, and upon being interviewed, I checked out their espresso station. Rancilio Techna espresso machine, which isn't the best, but, having experience on them, can pull excellent shots. The one thing that always sticks out like a sore thumb to me is that no matter how nice the equipment is (They have a Mazzer SJ and a Rossi RR45), the tamper is always in dire need of not existing. That is, I've worked at, or have experience with 6 coffee shops, of which, 3 have had legitimate tampers. These 3 had Reg Barber, Reg Barber Knockoffs, or solid SS tampers, all of which fit the 58mm groups. The other 3 have had 57mm tampers or those dinky aluminum double-sided tampers.

Which brings me to my question, in general. When one is hired as a Barista, is it their responsibility to achieve the consistency of the coffee shop they work for, or is it their responsibility to do the best they can do? In this case, I have 2 jobs, one with the wholesaler/roaster, one with a shop that serves their coffee. I have experience with the espresso blend, know how to dose it to pull the best shot.