Yes, my NA controllers were like this as well.
Reassembly doesn’t quite follow these steps in reverse order. Proper reassembly with the shoulder buttons is tricky. However, its much more simple to omit resinstalling the ‘1’ buttons until the controller housing is completely reassembled. They have one-way snapping clips on the edges, and appear designed to installed this way. Also, it’s good to double check the internal ‘1’ button switches are correctly centered inside the controller housing before4 snap in the ‘1’ buttons.
On my controller the button contact filament stayed inside the controller housing. Concerningly this exposed the contact ribbon for the buttons and sticks against the back of the logic board. However, the rest of the service with without issue, and the controller worked fine. This controller had a gray battery inside of it, and was likely a 60GB launch controller.