The company I work for has no signage anywhere which prohibits firearms, and our employee handbook says absolutely nothing one way or the other on the subject. Our VP (who calls all the shots since the Pres is semi-retired) recently installed a gun safe in his house and has a pheasant mounted on his wall, so I know he's pro-2A. In fact, he saw me surfing around this forum just last week and asked if I was considering getting my CHL. I told him I had started the process, and he said "Good" then asked me how the class was.
After that, he didn't dig for any more info, and I didn't volunteer any.
All in all, it's a very gun-friendly environment. That being said, I'm not going to say
anything to anyone about carrying at work. My wife will know that I do, but as far as I'm concerned, that's as far as it needs to go. I know I could probably very easily gain verbal permission to carry, but there's simply no
need to in my particular circumstance. If we had a provision in our handbook like the OP does, then I would of course have to reconsider my stance a little, but the point is still one that has been made numerous times on this site: concealed means concealed. Visibly, verbally, verily.