Changing heatrer core on an A/C truck?

[Rdub]

There's a great write up, with pics, in the FAQ section about changing the heater core on a non AC truck.... Anyone here ever chaged a heater core on an AC truck? Any different process than what is indicated in the FAQ? At one time I'm pretty sure there was a thread on here about it but, can't find it. I've been putting this off and need to get it done (71 GMC 4x4)..... any help would be appreciated.... thanks!