Dock connector form iPhone 4S compatible?

Something just happened with my iPhone 4 and the dock connector is no longer working. I have a spare parts from a couple iPhone 4Ss and both have working dock connectors. I've tried plugging them into the iPhone 4 MoBo and the MoBo connector seems to fit, so I'm guessing that standart did not change. I was reluctand to plug it in to an outlet as I was scared of a possible pin mismatch and frying something. Has anyone tried the 30pin dock connector from 4S on an iPhone 4?

P.S.

I'm short on cash at the moment - would like to avoid purchasing anything besides food. Otherwise I'd just go to a shop and buy a part.