When I was trying to figure out if I could go 308 I was probably speed reading and missing the parts about older surplus guns. I'm glad you point that out. Thank you .
These are probably some of the sights that I was remembering.
http://www.survivalistboards.com/showthread.php?t=140166
Firing .308 Winchester ammunition in a firearm specifically chambered for the 7.62mm NATO risks damage to the firearm and injury to the shooter.
Not quite as drastic but cautions against it unless you call the manufacturer
There may be others. These were first page results for "difference beteeen 308 and 7.62"