Mr Guiney was a father of four from Rathcoole in Newtownabbey.
His teenage son was with him, when his vehicle struck a lamp post opposite the New Lodge Road at about 06:00 BST.
Both died from their injuries days afterwards.
ICRIR assistant commissioner Amanda Logan has urged anyone with information to come forward.
“Any information, no matter how inconsequential it may seem, could be of critical importance to uncovering the truth,” she said.
“If you know anything about the circumstances that led to the deaths of Eric and Desmond, please share it with the commission.
“All information will be treated in the strictest confidence.”
She added: “The Guiney family has waited more than four decades to learn the truth of what happened that day.
“At the commission we will help them in every way we can, and I appeal to the public to assist us in this work.”
Posters and leaflets will be used as part of the witness appeal.
