damn, makes me glad i ordered mine oem a while back, or i could be in the same situation cuz i totally missed that u could get either of the drives (or maybe it didn't say that when i ordered mine). here's the text from the newegg site:
LITE-ON XJ-HD166S 16X DVD ROM Drive - Retail48X CD-ROM Access all format DVD-ROM/R/RW ,CD-ROM/R/RW title & disc Comes with Audio Cable, Manual and Power DVD Software. XJ-HD166S or, XJ-HD165H
it's pretty misleading if u ask me, but it technically does say that u might receive the 165 instead of the 166S.