I think Snoopy is still a neighborhood dog in this strip, he just happens to be in Charlie Brown’s house. Notice how CB says excuse me to Snoopy, as if he is a guest (although evidently a disruptive one). He wouldn’t do that if Snoopy belonged to him.
It’s cute how in these very early strips the kids treat Snoopy as if he is one of them, a kid who can understand what they are saying, well before Schulz gave him his own thoughts and fantasy life.
Reminds me of a Peanuts strip where Sally tells Charlie Brown that she is listed on the program for the school play. The final panel says something like “We also thank all the others who helped out.”
Do that? Yeah right! Good old Snoopy, how I love him! :o)