You can do this, but be very careful of any direct edits to your SQM as if there are errors in it then ArmA will crash like a drunken tiger on roller-skates. However, just changing the side of a man won't change the uniform worn, which would require a change to the class as well.
Rather than using Wordpad, I can recommend just about any other editor, such as Notepad++ (which has a nice
SQF syntax module) or ArmAEdit (which is a a dedicated Armascript editor). I mean this for general editing rather than sqm editing, which, as I said, is not encouraged.