Does Samsung manufacture LCD panels for Sony?

Yes they do, although that may change soon, see: http://www.engadget.com/2008/02/23/your-next-sony-lcd-tv-may-actually-be-a-sharp/

Sony, like many other manufacturers use parts from others. It may be possible for Sony to have a Samsung display in their LCD panels, and of course, I've seen many Sony chips in other brands.

Each manufacturer has its areas of expertise and it's not unusual (for economics) to purchase from someone else. Doesn't necessarily mean that there are any incompatibilities because of this, because each manufacturer will design the electronics around the parts that they choose to use.