To tell you the truth, I don't think you need to even ask anyone to record it. A few years ago, I recall one program of the History Channel that I really liked and eventually decided to do a Google search on it, and found a video of the whole 2-hour program on Google, and later on You-Tube (as nine 10-minute videos). From that experience, I'm expecting that, given some time, you'll be able to find it online somewhere.
I'm not sure if it would be uploaded on the channel's website after it airs on TV, but there is a chance of that happening. At lot of shows on that channel have full episodes available to watch online, so I think it's a good possibility.
Also, I recently found out that that program will actually be part of what will be called "Civil War Week". At this time, the only other program for that week that I know of is one about the lives of the two major generals of the war: Ulysses Grant and Robert Lee. There will also be special episodes of some shows, but I forget which ones. Go ahead and take a look on history.com to find out more.