The yellow 1919 Rolls Royce Silver Ghost, nicknamed the 'moon car', was commandeered by the group in Co Cork in 1921.
The car was fitted with two mounted Lewis machine guns and had a top speed of 70 mph, faster than other cars on the road at the time.
The Rolls Royce is believed to have been used in an attack on British troops in 1924.
They were shot at as they disembarked at the quayside at Cobh; a soldier and a civilian were killed in the incident.
This prompted the Irish Government to put up a £10,000 reward for information leading to the capture of the IRA unit.
The car was then abandoned, it was burnt and buried at the bottom of a bog.
Restoring the historic car was a task that James Black decided to take on, as his company specialises in bringing the models back to their former glory.
"It was delivered first of all to a Mr Adamson in Galway and he only had it for a very short time when it went into the hands of Oliver St John Gogarty, an Irish poet," he explained.
"Then it was captured by the Irish Republican Army at about 1920."
"I always knew about the car, it was quite a famous car although it was missing for many, many years."
Mr Black acquired the car three years ago and began work on it.
"The car had been burnt before it was buried. Fortunately it had been buried in peaty ground, so that the steel-work survived fairly well. About 85% of the chassis survived," he added.
"About 30 to 40% of the gearbox, back axle and front axle were complete. So we had quite a lot of it."
Mr Black said they used a Rolls Royce body from a car originally owned by the Spanish royal family to replace the burnt one.
The restoration man has plans to bring the moon car back to Co Cork to the scene of the attack that ultimately sealed its fate.