They both return long values, so there is no difference in the format. You can directly compare two long values, yes.
You may have meant to ask if you should expect those two long values to be the same, although you really only asked about the format and not about the content. Both contain a number of milliseconds since a certain point of time, so if you evaluate the two expressions at the same instant, you should expect to get the same value in both cases.
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