Surgery papers state gallbladder was necrotic, it was removed for stones & docs didn't mention it - should i be concerned?

Now that you had: The correct operation, no. But you were lucky that your surgeon was on the ball and got it out before complications set in.

No : Paper you mean pathology report , is the one the pathologist when received the specimen describes and after microscopic examination generates the report . Surgeon reports what was seen during procedure, like acutely inflamed gb with stones, will not know the mucous membrane is necrotic etc whole picture comes only after putting all reports together , don't be concerned. Speak to your doctor.