Its quite common for even major brands to buy most of their parts. I’m looking at an emachines right now that has a delta power supply, liteon dvd burner, western digital hard drive, amd cpu, nanya memory, msi motherboard (with emachines bios software but otherwise identical hardware to an msi retail board) etc. About the only thing that seems to actually be emachines is the case. One thing to be aware of though. Oem stuff might have different bios/firmware software even if the hardware is the same as a retail part. Look for 4kus as the manufacture when looking for firmware (4kus are oem liteon drives). You could probably also cross flash the firmware to liteon LDW-411S (I think that is the retail equivalent).
Here are some firmware possibilities.
IT looks like the official site is down right now for oem firmware but there are links for other sources. Here is where to look for more info (start with the faq sticky post).