Push-Push SIM card holder ESD protection required?
I would put them in. The ESD test involves putting the discharge probe near all the points that you can physically access and seeing if your device can handle the electric field generated. Looking at the sim-card holder design it appears that it would be impossible to direct the charge/field directly onto one of the internal pins given the large metal frame shielding them. Based on this it would initially appear that you don't really need any ESD protection. 

However you need to consider the situation when a sim-card is partially inserted by a human charged up with ESD. If you have a look at a sim-card you will see that the bottom surface is basically a set of metal contacts, and it is entirely possible for charge to transfer from a person holding it onto an internal pin. Since this is not an unlikely scenario I would include the ESD protection.

In the end if you have doubts about EMI/ESD protection measures you should always include them on the board design. You can always cost out the design later by leaving them off after checking your design passes appropriate tests, but doing the reverse is much harder.