Evidence in the game's files and speech point to them originally being called "Honor Guards" instead. Their rifle is named Kar-98k Rifle (Honor Guard) in the game's files, and Volksgrenadiers refer to them as "the Honor Guard" in their idle speech (they also make it clear they do not like them). Moreover, no unit in the game refer to them as Obersoldaten, even Obers themselves only have generic voice lines when activated (Achtung! Be ready!).
Personally, I think Honor Guard was a much better name. I suspect it may have been changed because it may have been implicative of the SS Honor Guard. Seeing as the unit was is obviously inspired by the SS, someone may have decided they were getting too close to real-life with the name and had it changed.
If anyone knows more about the change, perhaps they could share it?
![:) :)](/images/Smileys/smile.gif)
(added a poll because I can)