Why don't you speak to them yourself? The avionics shop may have reasons to not pass on all the details - if they don't understand the installation. Best to be pro-active in this game
I normally contact the firm in question and return the unit to them for checking. You don't need an avionics shop to
remove some piece of avionics. And reinstallation is just 4 screws and the connector in the back. And if it isn't your only (certified) primary CHT/EGT indication, you don't need it for flight anyway.