In 1991, Colt
came out with a 1911 pattern pistol
and dubbed it the 1991a1.
It has all the features of the 1911a1 and also the Series 80 firing pin safety. To many, this gun appeared to be the last 1911 style pistol that Colt will ever manufacture. Too many other brands with cheaper and better 1911 guns are out there and Colt had already announced that they will stop or drastically reduce their manufacture of civilian firearms.
The 1991a1 was not particularly good and mostly people bought it "because it's a Colt" and it retailed for about $450 to $500 which is not too bad but personally, I think it could be better spent elsewhere.
Fortunately Colt still makes 1911 pistols and recently came out with a reproduction of the WWII era Colt 1911. It is a very faithful copy of old slabsides that many grandfathers carried with them in the shores of Normandy all the way to Vietnam.
For a shooter and a base for customization the Colt 1991a1 is ok, especially if you feel better for having a real Colt. Personally though, I would go with a Norinco 1911a1.