I replaced one of my shackles for my 2000 Blazer, and am going to replace the other one when I have the time, but due to working full time, I can't. I also need tires and an alignment. If I was to get an alignment say tomorrow and replace the shackle in a month from now, will it throw it out of align?

 

You replaced it with a stock spec shackle, not a lift one or anything? If so then it shouldn't make a difference at all.