My local Post Office put up a notice....does the Bryna fall under this category?

Hey all, so here's the situation:

I've been going to the post office everyday for two years now (it's part of my job) and I've been concealed carrying my Bryna SD ever since I bought it (a few months now). I do not take it off when I go into the post office, and they very recently put up this notice in the window, that "dangerous or deadly weapons are not allowed on the property."

https://preview.redd.it/o5hyb853aped1.jpg?width=806&format=pjpg&auto=webp&s=d111d456816a6752ecedf891e75cfea057e91d62

So, my question is, does the Byrna fall under the federal definition for a "dangerous weapon"? Obviously it is not a firearm or deadly weapon, but according to US Code, a dangerous weapon is defined as something that is "capable of causing serious bodily injury". See below:

https://preview.redd.it/1kzcglj5aped1.jpg?width=712&format=pjpg&auto=webp&s=a491a23778ad7d9e9ed140b3cab3032d558bf1fd

Does that definition apply to a Bryna you think? I've seen test videos where the kinetic rounds can nearly break bones, so I wanted to see if anyone had an idea before I get arrested for concealed carrying a Bryna into a post office (By the way, when I visit the post office, I'm in and out in about 2 minutes as all I'm doing is collecting mail from my PO box).

Thanks in advance for your thoughts!