In all honesty, that seam should stay. Filling it in doesn't help anything because the back is a floating back, meaning it is supposed to have a tiny amount of play for expansion and contraction. One cold season and any filler would crack from top to bottom, looking far worse. Now, that paint job is another story.. not very good for a high end job.
The gouge in the side of the cabinet wall, BS on filler falling out. And really, a gouge like that can mostly be removed with steam and an iron if you really want to leave it there and mask it as best you can. Personally on that particular issue i'd steam it out (I did just that on a few spots on a local collectors game, you can't see where the gouges used to be). For me the only real catch point is that I don't want to get rid of the woodgrain from the insides of the cabinet as that is the 'original' look so going with a filler would require priming which in turn would virtually eliminate the original feel of the woodgrain.
Restoring isn't rocket science really.. it's directly related to the eye and toolset of the restorer and the budget provided. Give me 5k plus parts to do a restoration like hep gets and it'll look NIB too, but for 500 I can give it a run for the money as well
