Is it OK if I put a little bit of wet food in my dogs dry food?
Why would you put wet food in his dry food?
To get him to eat!
Why? Is he all skinny and losing weight?
No, he looks normal.
Then why would you coax him to eat and go over that normal body weight? If you get him to take food when he is not actually hungry, he is just going to put on weight and wear out his hips and knees earlier.
If I could get my customers to let their dogs eat what they need, and not what they want, I would die a happy man.