I received an offer letter after an accelerated interview period.

The offer letter I received demands an answer by Monday, and it refers to an agreement regarding proprietary information/inventions, the employee handbook, and a conduct code. When I asked to review these documents, I was told that I would receive them on my start date. I had to ask about vacation time, and was given basic information on the starting situation. They did supply information on other standard benefits like health care and 401K. The final stage of interviewing went very quickly, and I'm feeling some trepidation and pressure to say yes quickly. They kinda came at me like it was a done deal, and like negotiation wasn't expected. Am I wrong to think it's odd to join the company without seeing these documents, particularly since they are referred to in the offer letter? Perhaps they are considered somewhat confidential?