Based on picture at Chipworks, the M7 chip is under that black cover in the middle of the connectors.
Looking at the 5c Apple 338S1164 is in the same position as 338S120L and the same position as Apple 338S1117 (Cirus Logic audio codec) on iPhone 5. However 120L is much larger than 1164 so maybe 120L has the M7 functionality along with the audio codec function?
Can you see if there are any chips under the black cover surrounding the connectors to the left? The leaked bare board showed a chip location under that cover. Thanks!