Large White Pill, "m" On One Side, The Other Side Completely Blank

Updated
Anna Says:

Found a pill in the restaraunt which belongs to one of the diners, would like to know if it's important enough to try and locate the owners.

Pill is fairly large (~1 cm), round and white. The one side is entirely blank with no lines. The other size has a large "M" in the center (not in a box). I've tried looking through the forums but I don't see anything like that.

From the lack of code\dosage marks I assume it's not a perscription drug, but I'd still like to make sure.

Thank you very much!