Driveline Length/Factory Specs ???

I just ran an errand for a friend, dropping his driveline off to be shortened for his 72 Charger. Turns out, the spec he gave me came out of a chassis/parts manual, off the net. Are those specs given the center-to-center length, or (??) Thats the only shaft measurement Ive ever worked with, but it just occured to me that I'm not positive thats what factory books use. I assumed it was, but we all know about assuming... The shop likely won't get to it til mid next week, so I'm gonna have him do an actual measurement this weekend so that we don't have an "ooops" anyway, but I'm still curious...