The seatpost on my 51 cm, model year 2000 P3 rises at an angle of 83 degrees. Having said that, if you are focused on that parameter, you are not really looking at the right parameter regarding positioning.

Note that the extended seat tube does not align with the BB, or even close. I would not be surprised if this parameter changes with frame size or model year, maybe by a lot.

If you really want to understand the geometry, you should give some serious thought to the stack and reach parameters that Cervelo has begun to promote.