Removing the barrel-extension is not a problem. They will come off with ease. The only possible problem with re-chambering an AR barrel is that the gas-port is already drilled, and the chamber is already "timed" to the barrel-extension that is installed.
You would want to remove the barrel-extension to re-chamber it, but you would have to be very careful when you finish the chamber so that when the barrel-extension is re-installed, it not only times-up to top-dead-center, but the headspace is correct as well.
I have re-chambered AR barrels just to save them. I have had, over the years, several AR barrels with bad throats, or bad scoring in the chamber. Once the barrel-extension is removed, you can deepen the chamber with a finish reamer until it is cleaned up. In order to use the same extension, .0625" would have to be removed from the barrel-shank, and the chamber-mouth re-cut. In the past, instead of re-fitting the old barrel extension, I have fitted it with a new extension that will time-up after deepening the chamber by only perhaps .010". You may have to spin several barrel-extensions onto the shank before finding the appropriate timing, but I think it's better than having to re-cut the shank and chamber-mouth.
A short answer to the question is yes. Any AR chamber can be re-cut to any other chamber of the same bore diameter, with a caliber that will "clean up" the old chamber.