Was it a full fare economy ticket on a KLM one class flight?
If so, your company might have paid what is in effect a business fare.
Best way to avoid embarrasment is to ask the check in agent "does this ticket have lounge access.
If checking on line or at a machine, you can clarify at the lounge - you are unlikely to get a rude response if you make it clear you don't know if you can com ein.