I will have to ask the store manager, I suppose. I don't remember seeing a troop number, or any uniforms either.
It's been a long time since I was a scout, but I seem to remember having to wear my Girl Scout uniform whenever I was out representing the Girl Scouts. When I was trying to sell cookies, for instance...
I was never a scout, but the uniform rule you mention remains true to this day.
What you described is totally unacceptable. I really encourage you to get a hold of the GS council and tell them about it. Thnkgs like that givethe rest of the girls a bad name.