Re: Is this name inappropriate?
If you like the name, use it. But, be for warned that your boss very well may hold it over you, if that is possible in a government job. When you get one less point on a review or get passed for a promotion, these are all things that are considered, not just the job well done.
Sometimes in life, we have to be a little more PC than we wish. That term has a negative connotation for many. When I saw that name, the first I thought was the rouge postal agent... Especially the one in OK back in the mid 80s. I would assume many other's will too.
I have a friend who sorts for the USPS. He still thinks the term Going Postal is rude and uncalled for. For me, I try to stay away from names or sayings that might invoke a negative feeling in people. In popular culture, I think it is an appropriate name.