If someone claims that he saw or met Muhammad (Sallallahu Alaihi Wa Sallam) in the form of light while awake (not in the dream), would such a claim be true?
It is not possible for the Prophet (peace and blessings be upon him) to be seen, or to come to a person while awake, only in ones sleep (as was pointed out in another answer). Most importantly one must see the Prophet as he was, and not in any other form like the form of light or anything else. For the Prophet was not light, if one has seen a man in ones dreams that matches the description of the Prophet then what they saw is true, but if it is anything else then it is not true.
It's not true, because the only way to see dead people is in dream or in the other world. If someone saw the last imam, mahdi (peace and blessings be upon him), it can be true when he is alive.
But the prophet Mohammad (peace and blessings be upon him) is not alive in this world, so this can't happen at this time (we can't say things about the last day (ghiamat)).
It's not true, because there was no mention of such thing in Quran or hadith about prophet Muhammad coming to meet someone alive, except in a dream.
Another point is that nowhere from Quran and hadith it is proven that he is Noor or something like light. From Quran and hadith, his appearance is clear about how he looked.