Little boys little problems, bigger boys bigger problems

When the boys were small, Tim and I were raw and ragged from having two little bundles of joy to take care of. I still shudder when I think of the endless crying, whining, and sleepless nights. One of Tim's colleagues told him, "little boys, little problems; big boys, big problems." I think now that the boys are on the verge of the 4th birthday we have gotten to some bigger problems. Right now is it lying. I did not think I would be dealing with this problem so soon. I really was hoping to get some of the no longer acting like a baby, but still a sweetie time. Patrick shattered that idea yesterday when I picked the twins up from school.
It was show and tell day so both children brought toys from home to share. AJ brought his GeoTrack fire truck with mini fireman and PJ brought 3 similar looking dinosaurs and a mini GeoTrack cowboy. As we were leaving the classroom, PJ had 4 similar looking dinosaurs and told me three were his and one was one he had found at school. I said we can not take that dino home because it is not ours and that would be stealing and we do not steal. PJ protested and complained that he needs 4 dinos for a Mommy Dino, Daddy Dino, Adam Dino and Patrick Dino. I told him firmly no and to please put the dinosaur away so we can get going home. I left the boys to put things away in the classroom and proceeded to the front desk to chat about what to bring in for birthday (since I still can't get my act together to have a party for their friends). The boys come out and I ask if PJ had put the dinosaur back. PJ says yes. I try to pick him up and he backs up from me, so I know something is up. Then I ask where did he put the dinosaur and he tells me in his cubby. So I say, let's go see. The boys run ahead and enter the classroom. When I get to the classroom and check his cubby, there is no dinosaur in his cubby. (I actually now think he was trying to unload the stolen dino from his pocket before I noticed.) I was so upset with him. I tell them that lying is unacceptable and I am very disappointed in Patrick's choices. Then I ask PJ where is the dinosaur. He still doesn't fess up even when I am checking his pockets (Mommy getting really mad now). Finally, AJ tells me that PJ put the dino in his green jacket's zipper pocket. I find the dinosaur, remove it, give him a stern taking to, put the angry/crying boy in the car, put the other child in the car, and drive home were I get "look at my face, Mommy, it is not happy". Once home PJ promptly goes to a time out in his room. Apparently, he is very sorry and "won't ever do it again." Time will tell.