As a mother to 2 teenage boys (17 and 19) I can tell you that the behaviour you are seeing is totally normal! I'd be shocked if you didn't see it to be honest!!
My boys can come in and out the house, eat their meals etc and some days I hardly get 5 words out of them. It's not because they don't have manners (that's the one thing my kids ARE good at) it's just because teenagers become unsociable with their parents
No their mother doesn't have the right to call the shots on what time you visitors etc leave esp as the boys are a bit older. I'd understand if you were having p!ss ups and the boys were younger though.
I also have an ex and he has a wife now, so my boys have the step mother. She was a right cow to them growing up, so harsh to them all the time, to the point that it damaged their relationship with their dad. They no longer wanted to go and see him. Funny thing is, her children that she has with him now are little mongrels and run riot, she has no control over them at all!
Anyways, what I am saying is try not to take it too much to heart. It's not that they don't like or respect you. Treat them as people and respect that they have times they don't want to talk also. Be there and open when they do want to talk and they will come around.