It almost certainly wasn’t.
The Dark Lord shed the name of Tom Riddle as soon as it was possible for him to do so, and even when he was young, it was the name of Lord Voldemort that he expected wizards to fear.
“TOM MARVOLO RIDDLE
Then he waved the wand once, and the letters of his name re-arranged themselves:
I AM LORD VOLDEMORT
‘You see?’ he whispered. ‘It was a name I was already using at Hogwarts, to my most intimate friends only, of course. You think I was going to use my filthy Muggle father’s name for ever? I, in whose veins runs the blood of Salazar Slytherin himself, through my mother’s side? I, keep the name of a foul, common Muggle, who abandoned me even before I was born, just because he found out his wife was a witch? No, Harry. I fashioned myself a new name, a name I knew wizards everywhere would one day fear to speak, when I had become the greatest sorcerer in the world!”
- Harry Potter and the Chamber of Secrets, Chapter 17 (The Heir of Slytherin)
As soon as he could, he shed his old name and later re-emerged into the wizarding world as Lord Voldemort.
“There he showed his contempt for anything that tied him to other people, anything that made him ordinary. Even then, he wished to be different, separate, notorious. He shed his name, as you know, within a few short years of that conversation and created the mask of “Lord Voldemort” behind which he has been hidden for so long.”
- Harry Potter and the Half-Blood Prince, Chapter 13 (The Secret Riddle)
Once Tom Riddle disappeared, nothing further was heard of him by majority of the wizarding world who didn’t know his new name.
“But before they were sure beyond doubt that the cup and the locket were both gone, the assistant who had worked at Borgin and Burkes, the young man who had visited Hepzibah so regularly and charmed her so well, had resigned his post and vanished. His superiors had no idea where he had gone; they were as surprised as anyone at his disappearance. And that was the last that was seen or heard of Tom Riddle for a very long time.”
- Harry Potter and the Half-Blood Prince, Chapter 20 (Lord Voldemort’s Request)
After shedding his old name, the Dark Lord wouldn’t have considered the name “Tom Riddle” worthy of inclusion of the Taboo. He left that name and identity behind him long before then.