IDK guess I am a little different than others - we had a monitor but didn't use ours right away. So if it were me, I'd return mine and wait on the other. But then again, I do understand wanting to have it for when you do need it as it can be a little stressful. But as a TTM I know we won't even hook ours back up again for a few weeks yet. Pretty sure I did not feel that way the first time around tho.
Based on what you told us, I don't think this guy is going to come through with the monitor. It could be really awkward to call him out on it and, for me, it just wouldn't be worth it. I would keep the monitor I purchased and just not expect a gift from him. I'm sorry this guy is so flaky
I say keep the monitor that you bought and get it set up for your own peace of mind. If he happens to give you one, I'm pretty sure BRU would at least give you store credit for it, which would come in handy for something after baby comes.
Re: Opinion on baby gift that we have not received yet
I hope he actually comes through!