that's what you say when you know he's around and can hear you...
If you say "У нас есть ..." it will mean that we have many bosses and (at least) one of them is good.
Напомните мне, почему нельзя:" We have GOT a very good boss"? (Трёх братьев, f.e, можем "иметь" (in such way - "заполучить"), а начальника нет?! :))) )
Hmm. I can't really respond in Russian, nor am I good at explaining, but I will try.
"We have got a very good boss." is broken English. You do NOT need the word "got" for that. I think you are thinking of "We have gotten a very good boss.", which is a bit of a different sentence than the one we have here.
I give you a scenario. A group of people know this person who is a very good person at doing things like managing. Let's call him Вадим. Вадим is then nomimated(chosen) as the boss. After the nomination, the group of people say, "We have gotten a very good boss! Yay!"
Another scenario this time, related to that same boss this time. Imagine an interview. The interviewer asks a worker of the company, "How is your boss? Is he a good person?" Since the boss has ALREADY been chosen in the company, the worker replies, "Yes, we have a good boss."
CONCLUSION(?): So there is this "уже" that is already implied in the correct sentence. While the one with "gotten" is like a "at that moment" thing. I hope this helps.