It might help keep the barrel straight and it might help relieve stress after the rifling process. However, many good barrel makers will stress relieve the barrels anyway and for those who would perchance like to have your barrel Teflon treated, it is sprayed then baked at 600 to 700 degrees then slowly cooled. This too probably helps with stress relief as well.
The most accurate muzzleloaders out there are better shooters than most any centerfire as it is, so why spend the money on a gimmick. Those Knights are not going to outshoot my White nor most any other gun either. I know people who have tack driving CVA's and the older Knights, like the MK85, were incredible shooters. I would save my money and get your gun Teflon Coated. That is the best few dollars you could spend on your gun and for those interested in that you can check out our website or
http://www.blackicecoatings.com
Much Aloha,
Tom