Actually, the quality started to improve in the mid-70's when they began to move away from the "forest of rivets", retractable landing gear/movable control surfaces toy-like kits and started to add details like moulded instrument panel detail and subtle raised panel line detail.
For example, the mid-70's vintage B-26 is quite a nice kit, albeit with movable tail surfaces. Arguably, this kit stood up pretty well and was only recently bettered by the Hasegawa release a couple of years ago.
Vance's Magister mentioned above dates, I think, from somewhere around 1976 and is, as noted, reasonably finely detailed for its size.
If you want "old school" look at something like the Beaufighter TF Mk.X which dates from somewhere about 1958. The moulds for this kit have been run for so long, the framing on the canopy moulding has all but disappeared.
At one time, some kits (before the advent of moulded IP's and IP decals) included a crude representation of the IP printed on the instruction sheet, to be cut out and glued onto the flat featureless IP.