The earliest clowns had no ears. Sometimes a red ear muff was applied. Ears were added very early as their 1904 catalog shows clowns with ears and clowns with muffs. Some collectors say that all clowns had either ears or muffs and those found today that are earless have had their muffs fall off. Nevertheless, I think that clowns were made both with and without muffs. Schoenhut catalog illustrations support this contention. 
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Muffs

Some early clowns were fitted with little red muffs over the ear area. These clowns are very rare.

Earless

Some clowns are both earless and muffless. This clown shows no evidence of ever having anything attached to the ear area.

Ears

Very early clowns usually have ears - if still attached. These leather  ears were inserted into holes in the side of the head. They were painted white and trimmed in red. 

(Need photo)

Large ears