That could be- I haven't read the books since the last one came out. This is what I'm seeing on the HPWiki:

Having embraced the Dark Arts he encountered in his travels, the former Tom Riddle, now known exclusively as Lord Voldemort, raised an enormous army comprised of followers he recruited both at school and afterwards,

That suggests to me that the early Death Eaters grew up with him as Tom Riddle, and it was just a name change. If the "Voldemort = Riddle" thing is poorly known, it's probably because no one has reason to know that his name was Riddle (like, for example, most people have heard of Stalin but haven't heard of Dzhugashvili).