Hello, I put on my first brisket this morning in my split door brinkmann charcoal smoker. It is 5.5lbs I put a rub on it last night and started it this morning just after 7 it has been on for about an hour and forty min. and I am at 125 internal temp is this normal? I am just concerned the temp guage on smoker is not accurate. I just want my first brisket to turn out good.