Am I my body? MMP uses "I am my body" or phrases like it several times in PoP.
BEGIN QUOTE
Insofar as it stands before me and presents its systematic variations to the
observer, the external object lends itself to a cursory mental examination of its elements and it may, at least by way of preliminary
approximation, be defined in terms of the law of their variation. But I
am not in front of my body, I am in it, or rather I am it. Neither its
variations nor their constant can, therefore, be expressly posited. We do
not merely behold as spectators the relations between the parts of our
body, and the correlations between the visual and tactile body: we are
ourselves the unifier of these arms and legs, the person who both sees
and touches them.
END QUOTE
Note that he says that "I am in it, or rather I am it." What he means is "I am my body," and the modern translation puts it that way. Unfortunately, Kindle won't let me copy/paste from the text, so I am using the older online version.
I don't find MMP's writing to be very clear, which is why I quoted a secondary source in the OP.