http://www.guns.com/2017/06/20/does-nras-self-defense-insurance-disallow-training-for-1911s-revolvers/
The course is asking the students to bring Glock-type guns or DA/SA handguns. This could be for various reasons, but uniformity doesn't seem to be too far from it.
What is also interesting is the content of the class.
The class is $850 for 3 days, which is not too far from some instructions available from other recognized instructors.
https://www.nracarryguard.com/training/in-person-firearms-training-courses/upcoming-classes/register/?ClassID=442437
The content
Includes: Safety and Weapons Awareness; Pistol Ready Positions; Fundamentals (stance, grip, holster draw, sight alignment, trigger press, recoil management, follow through, economy of motion, self-critique); Treating a Malfunction; Live Fire Progression Drills; Combat and Tactical Reloads; Drawing from a Holster; Low Light/No Light Shooting; Combat Reload while holding a Light; Key Components to Carrying a Concealed Weapon; Carry Location Options (i.e. waist, ankle, purse, etc.); Real World Scenario Based Training (Airsoft scenarios)
The course seems to include some topics that are generally not offered in one package such as using hand-held light. Furthermore, there will be a force-on-force as well. This is a part of training that is really hard to find for a lot of people. IT is also difficult to set one up.
Overall, the course seems to be geared towards teaching some variety of basic skills and uniformity was imposed. At the bottom of the description,
We will not allow revolvers or 1911s as your primary firearm in this class.
You should bring a secondary firearm that you carry concealed, as well as a holster for such. We will run the course with a primary carry weapon and then run a course of fire with a secondary or back-up gun to evaluate the differences. Please bring at least 40 rounds of ammo appropriate for your carry firearm for this portion of the class. Revolvers, 1911s and/or subcompacts can be used for this portion of the class.
So primary firearm will be limited, but there is not for the secondary firearm.
