issue with overclocking the ivybridge cpu is the same as haswell. intel crippled their oc headroom by using thermal paste under the heat spreader so they get to a point where they overheat much quicker. how much paste they used is the main determining factor in how high you will get with any cooler.
the batch number and stock vcore is a rough indicator of how it will perform at the extremes of its envelope but stock cooling is not going to get it that far

it could be pushing the temps at stock speeds with the stock intel cooler. it could be you like your ac and the cpu has the perfect blob of tim which will let it do 4.5ghz with it. from here i have no real way of knowing.
the choice of motherboard and power supply will also play a role, but to a lesser degree than on older sockets.