Yes, sorry....I made a boo boo....got mixed up with the SA 600 class. I'm pretty sure they had only 3 windows initially, but then the 4th window was added at the front of the observer's position on each side. IE: the panel behind the driver's left shoulder, close to the cab door, was originally solid steel, but later changed to a glass window.
My apologies for the slip-up.
Bill its no big deal & an easy one to do, especially with the split sliding windows. The later 45's that had the modified Beclawat windows & some having the tinted glass makes the sighting of the individual frames hard.
The other aspect is that the as delivered versions all had the drop down window on the firemans side, rather than the later fitted rubber sealed window as found on the drivers side. The idea was ok as it was supposed to allow for more air flow with that window open, the problem being that the theory was fine but they idea was flawed as the sliding front panel covered up the window & little air flow occurred.
The other issue was that when opened the top latching mechanism never worked properly, meaning it was almost impossible to fully close the window, & most were then sealed in place with the catches being removed. The roughness of the 45cl also meant even when fully closed there was still strong drafts coming from the top & around the sides of the window tracks.
I never got on to a 600 class except when the first one came to PTK, but had to be sent back to SA for approved mods to be done, so cannot really comment other than to say that the one I looked at one the day in PTK, they had better crew amenities including sound proofing & the skins on the cab roof did help reflect the suns heat. Although I thought a backward step with the older A7 type brake valve.