Either this guy is a total novice or, as everyone so far has said, he is trying to con you for a new set of strings.
Most people, certainly the players who are any good, will change the set up and strings on a bass as soon as they get it and before they do anything else. I also check the intonation. I bought a bass just before Christmas and it had newish strings on, which I wasn't expecting. I have the set I was going to put on still waiting in the bag but I wouldn't even have mentioned it to the seller if the bass had turned up sporting a totally dead set.
Then there's the battery. If the bass is active I always change it. That's the point where I know I'm good to gig with confidence in the new instrument.