96 xj gas gauge issue

ok, so my fuel pump went out after 280K and i was away from my home so i had to tow it to the closest station. They replaced the fuel pump with a Bosch brand, which fixed the pump problem But now i noticed that my fuel gauge is off by about 3.5 to 4 gallons. i noticed it when i went to fill up the tank when the gauge was below the large mark on the E side. I topped off the tank but could only get 16 gallons in the tank and the gauge wont go past the large mark on the Full side. So my question is Did they screw something up or what? is it something that needs to be re calibrated or ? it was fine before they replaced the pump but i want to make sure before i go back up there and make them fix it:mad: