Old kits came with clear window inserts for all the tiny windows which created difficult assembly/paint decisions. Kit's like this have all the window holes with no glass which I find curious. Most kits come with window decals which look great in 1/144 scale so the idea is to fill the window holes in the fuselage, make it nice and smooth and put the window decals on like so

Now, I read a recent build thread where the guy did partial painting, filled the windows with resin like I did, polished the windows then put the fuselage together, masked the windows off and fixed any seam work and finished painting - look brilliant, but not going to tackle that on this monster