This paper has some information about the narrow angle camera NAC of LO. The focal length was 610 mm and the angle resolution 4.4 arcseconds. Images were stored on 70 mm film and developed and scanned later.
The NAC of LRO has an effective focal length of 700 mm and 10 micro-radians per pixel. The electronic image sensor has 5064 pixel.
4.4 arcseconds are 21 µradians. But the 4.4 arcseconds are based on photographic images resolution given in line pairs, not pixels. 2 pixels are needed for one pair of lines. The resolution of LO is therefore 2.2 arcseconds or 10.5 µradians per pixel, very close to 10 µrad.
At 46 km height, the Moon's surface resolution of LO was 1 m (line pairs). The resolution of LRO was 0.5 m per pixel at 50 km. Again the resolution of both orbiters is very close.
The very sophisticated electronic image sensors of LRO are an enormous progress to the photographic image system of LO needing a film supply and chemical development. But am I right there was no progress in optical image resolution?