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One may observe that MakeBoxes does not give the actual Box form of various expressions:
MakeBoxes[{1*^4, 000123, a*b c}]
RowBox[{"{", RowBox[{"10000", ",", "123", ",", RowBox[{"a", " ", "b", " ", "c"}]}], "}"}]
The 1*^4 was expanded, the leading zeros of 000123 were stripped, and the dist...