I have a Pi B v1 and it's analogue out is definitely stereo. The problem I had (which is persistent right across their range of boards) is the popping sound that happens at the start of audio because of the voltage change on the chip. There's been some workarounds to try and reduce the severity of the popping (namely building a fast volume change at the start of clips and using an "always on" sound server like Pulse. But annoyingly the only real fix seems to be to using a cheap USB audio adapter. So I've now come to the conclusion that the Raspberry Pi isn't the best development board for audio projects. However for $35, I have no regrets in buying one (in fact I still bought a 2nd one even after learning about the aforementioned issues).