Don't RF devices need to be shielded to pass FCC?
I don't think board level shielding is a requirement to pass FCC, unless it's modular, and even then I'm not entirely sure.

Also, that's the same reason there's not a Modular Approval Request Letter because it's not modular. It looks like a self-contained product, not something that connects to something else. I think you're treating it as a Bluetooth module, which do have shielding and are meant to be used with something else, but what you linked isn't a module.