Howdy
As stated, the Colt Cowboy was an attempt by Colt to compete with Ruger for a moderately priced Single Action revolver. It did feature a Ruger like transfer bar assembly. They are not the 'Fourth Generation'. The 'Fourth Generation' is a misnomer for those 3rd Gen SAA revolvers that reverted to having a removable cylinder bushing. According to collectors, there is no such thing as a 4th Gen, the true SAA is still in the 3rd Generation of production.
The problems with the Colt Cowboy were mostly related to QC in the early guns. They soon gained a reputation for poor quality, even though Colt corrected many of the problems in later production. But the Cowboy reputation was already ruined and sales were not good. Eventually, Colt stopped producing the Cowboy.
According to the Standard Catalog of Colt Firerarms, by Rick Sapp, Colt Cowboy production started in 1998. He does not give any total production numbers, nor does he state when production ended. He does say that 'parts for the cowboy were manufactured mostly in Canada and finished and assembled in the United States.
I had the opportunity to fire a pair of Colt Cowboys a few years ago. I saw no problems with them either as shooters or from a quality standpoint.