I have my grandfather's 992B he wore while engineer on the B&O's Capitol Limited and Ambassador trains up till 1946. It winds fine but I cannot get the stem to pull out. I am assuming the stem does pull out to set the time, right?

The watch is lever set. Do not continue to pull out on the crown, it is for winding only. To set the watch you will have to unscrew the front cover of the watch. A lever will be obverved sticking out slightly in the right quadrant of the dial. Carefully slide out the lever. You should then be able to adjust the time by turning the crown. Then slide the lever back in, screw back on the front cover and you should be good to go.

This military 992B has the same lever. You just unscrew the front Crystal Bezel, pull out the lever and then you can set time using the winding crown. Be sure to push the lever back in before trying to reassemble the front Crystal Bezel.