NP203 Question

[Gene]

Ok, so I hate to be "that guy" who asks all the obvious questions about 4 wheel drives, but i'm to the point in my build where I want to make sure that I have all the correct parts for my truck. I'm pretty sure that the NP203 did not come in a 67-72 truck? Am I right? And I know that originally they were a full time 4wd transfer case right? Ok, so here's my problem. I'm researching trying to figure out what transfer case I have and after looking at many pictures of various cases I decide that I have a NP203(22 inches from front of case to rear). But I read that there is a part time upgrade that is available for these to make them work like a NP205. So i'm working the levers on the side of the case and one lever has three positions, one locks the front and rear together, one is neutral, and one seems to just power the rear? The other lever has 2 positions which i'm assuming is High/Low? So does it seem to you all that I have a transfer case that has been modified to part time 4wd? Thanks!