The CP2102 does support a Serial-Number ID just like the FDTI chips.
It's entirely possible that I'm mistaken, but I have several of these device (or the 210x family, for sure) at work. When using them with linux, udevinfo couldn't find any information that was unique to the device. This is a serious problem, as I have a box that has 4 of these units installed, and I don't have a good way to differentiate between them.
Maybe they're simply blank and require use of their mprog-like utility to configure a serial #?
In any event, it was definitely an SI labs CP210x driver than kernel dumped my mac years ago. This left me dead against the devices, and seriously disappointed in Apple (although in fairness I don't know if OX X could have prevented a bad driver from causing a dump, once I had installed and executed the code).