There were three leather hip holsters made for the 1911 and 1911-A1.
The Model 1912 Mounted or Cavalry holster had a long drop loop with a swivel that allowed the holster to pivot when mounting and dismounting.
On the back was a strap and buckle so it could be secured to the leg.
These were made in Russet colored leather, and were issued up until early WWII to cavalry and early armored forces.
The 1912 Mounted was intended to be used only by the cavalry, but was often used by other services including the Navy and Marines.
The Model 1912 Dismounted or Infantry holster was to be used by everyone other then the cavalry.
It resembled the Model 1912 Mounted except the long drop loop doesn't have a swivel.
Instead it has a second brass stud up on the flap so the flap could be rolled over and pinned up out of the way for a faster draw. It also has a strap to strap it to the leg.
This was supposed to be the standard issue 1911 pistol holster for everyone but the Cavalry.
The Model 1912 was not at all popular with users, especially the Infantry and Navy, so the Model 1916 Dismounted holster was developed.
The Model 1916 did away with the long drop loops and leg strap and was the standard issue for all users until 1984.
There was a Model 1916 Dismounted made for a short time for use with the new M9 Beretta as a parade holster.
The Model 1916 Dismounted is sometimes called the 1936 but the official designation was the Model 1916 Dismounted holster.
The Model 1916 was made in standard Russet color, and during war time it was also made in plain tan leather to speed production.
The Model 1916 was often oiled with Neatsfoot oil or with shoe dubbing. This gave it a darker brown color, with a very dark brown common during WWII.
After the Korean War, about the mid-1950's the military went to black leather for the Model 1916.
Often, left over WWII production Model 1916 holsters were dyed black. Many of these were dyed only on the front side to prevent the black dye from rubbing off on expensive dress khaki pants.
For a look at the three US issue 1911 hip holsters, Pacific Canvas & Leather make decent replicas in China:
http://pacificcanvasandleather.com/
For the very best replicas of them all, El Paso Saddlery made exact replicas of the Model 1912 Mounted and Model 1916 Dismounted:
http://epsaddlery.com/
There was a non-official 1911-A1 holster that was bought by some units in the 70's especially MP units.
This was also a John Bianchi design and was the M-66 Ambidextrous leather holster.
This featured a flap that could be unsnapped and removed, or pivoted up and forward to clear the gun for a fast draw.
It was set up with snaps on both sides so it could be worn right or left handed and cross draw.
The military didn't officially adopt the M-66, so in the 80's Bianchi developed the UM-84, or Universal Military Model 1984.
This can be worn on either side, as a cross draw, as a drop loop thigh holster, as a shoulder holster, and by folding the flap plastic loop under, it can be used as a no-snag holster by paratroopers.
It has a emergency cleaning rod in a slot in the front, but the rod is not intended for use other then emergency.
The official US issue version is the M12 sized specifically for the M9 Beretta. While it will also fit the 1911-A1 and others, it's a best fit to the M9.
The M12 comes with a plastic tube that fits in the bottom of the holster to keep the holster sized to fit the M9 during storage of the holster.
In the Bianchi series is a newer UM-92 that features a polymer trigger guard shield that offers more stability.
There's also a UM-84R for revolvers, and a UM-84III for compact autos.
Last, Bianchi offers versions of their "Accumold" formed nylon holsters for the 1911 series pistols.