The little white pins are just spacers that were used in the assembly of the windows since the grey putty stays squishy forever.
Have a look at the following thread--it eventually gets on to rebuilding one of those wing windows.
The windows on the 70's trailers apparently came in two configurations, one kind could be rebuilt without completely removing the window frame from the trailer, the other can't. At a glance your windows look similar to the ones I have, which had to be completely removed from the trailer in order to disassemble them. I took apart both of my windows, rebuilt them as single panes, saved the inner glass on each of them for the next time I have a broken window. It wasn't too bad. The worst part of the job was dealing with the four screws that hold the window frames together--they broke off on the first window, so I had to spend a lot of time digging out the broken screws. My second window used stainless screws and they came out in one piece.