There was a hint in the first draft but it was removed to save space. Now the only way to find it is to suceed a Wisdom (Perception) check (or with a high enough Passive Perception) that is really not that hard for 5 level characters.
And when they see that the false tomb is a dead end they might investigate the other rooms.
Layout and styling (apart from the map) is done with homebrewery.naturalcrit.com . I should have credited this wonderful websiite, but that is my first jam and I didn't really know how to incorporate all the credit.