No they are not
Although JK Rowling has never addressed this anywhere in interviews, Pottermore, twitter, or anywhere else, she has showed the reasons why she picked those two names.
Harry was picked because Rowling likes the name
Question: From where did you get the name for Harry Potter?
J.K. Rowling: 'Harry' has always been my favourite boy's name, so if my daughter had been a son, he would have been Harry Rowling. Then I would have had to choose a different name for "Harry" in the books, because it would have been too cruel to name him after my own son. "Potter" was the surname of a family who used to live near me when I was seven years old and I always liked the name, so I borrowed it.
(About the Books: J.K. Rowling's live interview on Scholastic.com)
Tom was picked for the in-universe reason, to give Voldemort an ordinary name for him to hate, causing him to adopt a different name instead.
Ask for Tom the barman — easy enough to remember, as he shares your name —”
Riddle gave an irritable twitch, as though trying to displace an irksome fly.
“You dislike the name ‘Tom’?”
“There are a lot of Toms,” muttered Riddle.
“Firstly, I hope you noticed Riddle’s reaction when I mentioned that another shared his first name, ‘Tom’?”
“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)
It should also be noted that there is no character named "Dick".
The closest you get is random side character Dirk Cresswell, the Head of the Goblin Liaison Office, who is mentioned three times in the entire series.
Credit to Richard, Voldemort, and Rand al'thor.