Ok, maybe the proper term for the clear spacers isn't lammer, but it is relatively common to call them that.
I don't think a lammer has to have a denomination, though....
The term lammer is used for many different things.

"Used to mark the position of a player who has missed their turn to pay a blind. When the player returns, the missed blind(s) may be paid immediately, or the player may keep the lammer and wait to play until the unpaid blind comes in turn. Which indicative lammer is used depends on the game being played and/or which blinds are missed."

In this link, there are MANY lammers that do not have denominations on them.

Lammers: Lammers are plastic, chip-shaped tokens with text written on them. Most commonly used is a dealer button with either the word "DEALER" or a "D" written on it; this item (also known as the buck) indicates who shall deal next. In a casino setting, lammers are also used to indicate which variant is being used, whose turn it is to pay the blind etc.., and lammers are also a name for "chips" awarded in satellite tournaments as buy-in chips to larger tournaments.

Interestingly enough, according to dictionary.com, lammer isn't even a recognized word.