I tend to disagree.

Even with same weight/same tires/same everything, different teams will use different algorithms to control the car and to take decisions. There are a thousand ways to make a car follow an "optimal" path and I doubt everyone will use the same, and even if they do every team will have their own implementation which will lead to small differences.

Adding to that all the uncertainties brought by measurements of the outside world (correctly estimating where are the car and the other cars) and the possible interference between the different car's sensors (if they run all at once like in real F1), we would certainly have surprises. Controlling a real car is not the same as controlling an AI in a video game, a lot of mistakes can be done.

Source: I work as an R&D engineer in an autonomous vehicles company