It's the same in our Council. All the girl troops are 4 digits starting with a 4. We will only be using 3 digits on our uniform though, mainly because we couldn't really think of any meaningful numbers that were 4 digits beginning with 4.
I think just from what I've seen all the packs in our council start with 0, boy troops 1, and venturing crews 2. I will make a wild guess that either sea scouts or explorers start with a 3. But only the venturing crews actually use all 4 digits on their uniforms.
I am going to go on a different tangent regarding Webelos 3, and New Scouts
William "Green Bar Bill" Hillcourt wrote a 6 month plan to teach New Scouts how the patrols and troop should be run. It could also be used to train an adult led troop's PLC to become a Scout led troop. It is in his 3rd Ed. Scoutmaster Handbook from 1929. I don't remember which volume it is in, I lent the book out and never got it back. But based upon my memory, Bill's plan IS essentially how Webelos is suppose to be done based upon my experience as a Webelos, and the training I have done and taught.
In a nutshell, the SM initially acts as the PL, or if redoing an existing troop the SPL with PLC, and explains and demonstrates what is expected. Everything, pitching tents, cooking, KP, etc Is initially taught by the SM. Over the 6 months, more and more responsibilities are given to the Scouts until by the 6th month, they are running it on their own.
One caveat, because Bill's program is not advancement oriented, but rather skills oriented, if you have girls pushing to get Eagle in a hurry, Bill's program is not for you.
You may need to update Bill's plan to keep it current, i.e. no ditching of tents. But when I read it a few years back, I saw it's usefulness to a New SM who was having challenges, and it helped him out tremendously, He started 3 or 4 troops using the plan.