1993 Sierra 4x4 4L60e Transmission indentifying one?

Is there a visible difference or a casting number so I can tell I'm getting the right tranny for my truck? I know since it's electronic I have to have the same year or some things won't work right. Anyone found some online removal instructions for it? I've done tranny's on some of my cars but its always nice to have some tips on certain vehicles. Thanks.

1993 4l60e has a square oil pan and 16 bolts holding the pan in place is one way