Yes, local LEOs have authority to enforce federal laws. For example, bank robbery is a Federal crime and local police are often the first responders and arrest the bank robbers.george wrote:
Would the local LEO have any authority to enforce a federal law like GFZSA? Likewise, would they have authority to enforce at the post office?
They would know I am carrying, because if I get pulled over for something in a school zone in Oklahoma, while carrying with my Texas CHL, I would have to inform them when LEO ask for identification.
Strangely, the US Attorney argued in front of the Supreme Court this year in opposing Arizona's immigration law that local police do not have the authority to enforce federal laws. I guess bank robbers will have a field day if SCOTUS buys that argument.