Absolutely not. I do push my feet into the uprights to maximize stability though. With the right shoes I don't need to do this but it's the most consistent way that I've found to work.
It's normal but and in strengthlifting more can be better from a competitive standpoint. However, if your goal is general strength and conditioning, I don't know that bending back beyond a "standing incline bench press" is necessary or healthy for longevity. I want to clarify that some people bend back just fine and experience no pain but i've had multiple lifters complain of low back pain and sciatica because of it and the seated press helped reduce the degree of layback on the standing press to the point where they no longer experienced these symptoms.