Well it may have been, but it differs significantly from most "off the rack" euro frames in geometry. Eg. the Colnago C-40 or C-50 has significantly shorter chainstays and fork rake although the Colnago has a similar head angle in the midrange sizes. Most standard euro frames have a steeper head angle, shorter stays and shorter rake than the Roubaix. Many frame builders list their head angles as proprietary, so sometines it's hard to compare, but the Roubaix's fork rake and stays are definitely longer than most.

It is more like a bike that is designed specifically for the Paris-Roubaix race. If you read Cyclingnews.com reviews of these bikes, they will generally be described as having more rake and longer stays than regular race bikes. See their coverage of the Bianchi bikes ridden by Alessio this year.