I'm no expert but I think you should.
As a rescue, you probably don't know his previous history and four years is quite a long time in a dogs life.
I'm no expert but I think you should.Hello, I recently recused an 4 year old malamute . He is not fully socialized with other dogs but I'm not too worried about that. I am worried about people, with us he is fine now. At first he was alittle touchy with us pulling his collar where he would do a snap but no blood or pain from it . He dosnt do that anymore to us but not sure on other people. Well today I took him to the vet for the first time with me and he snapped and growled many times and jumped up on them to get away. I had a muzzle on him but it was still pretty intense . He acted this way when they held him down to listen to his heart and then they tried pinning him in a Conner to finish but he just growled and tried to bite them . I'm not sure if I should get a trainer for his aggression or not.