Quick 4wd question, 87 FSB

I am a newb to 4wd vehicles. I am going to look at an 87 FSB, 300 I6, 4spd manual w/ manual lockouts. How do I check to see if the 4wd works properly? Do I place the transmission in neutral, then get out and turn the lockouts, then select high or low?

TIA!

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