Cspro, firstly I need to state that I am unsure of whether or not you are able to OC your Laptops GPU, as you're the first person I've read anything about OCing on a laptop GPU (if OCing on laptops is common, then please excuse my ignorance).
However, if you are able to, you're going to look at different temperatures. They may variate a degree or so, but the general answer to your question is; Yes, anytime you OC a piece of hardware, you're going to generally accept that the temperatures are going to rise due to increase output of the device (it working harder).
That's quite interesting to hear, as I'm mainly a desktop person myself, but I will be looking into purchasing a (new) laptop in the future, so it's nice to know that OC is more common on them now. I hope you resolved the question you had by the little information I could provide on the general consensus of temperatures and overclocking!
I know I'm necro'ing, but this thread came up when I Googled OC'ing my GT 650M. Anyhow, it's not too complicated to do and YES, it will increase your temperatures. Consider getting a cooling pad and make sure to monitor your temps.