he might. might being the key word phil. really depends. IMO a clam that small, and a clown as big as yours... i wouldnt doubt the clam would get ultra mad.
The clown will most likely not hurt the clam, clowns have hosted in many corals, I would see how it goes and if the clams shows signs of irritation I would remove it.
my new oscillaris clown hosts an empty clam shell in my tank. The clam shell originally came with a toadstool leather inside, but its empty now. The clown loves to sleep in it.
My percula has made my clam his home for several years. Lies on his side in the mantle every night and defends the clam during the day. If my hand gets near the clam I get nipped and tail slapped. Took him about a year to train the clam to not completely close up when he is nearby.
Gary