When Arthur (Jerry Stiller) runs out of the house to the Good Humor Ice Cream truck, you can see that he stops at the porch. Immediately after, Doug (Kevin James) runs outside and you can still see Arthur standing still on the porch as Doug, supposedly calls after him running.
In one scene Deacon say to Doug that he's been working at IPS as long as Doug. However, in a flashback scene in another episode, that Deacon had already been working there when Doug started.