It is known there is a fairly wide variation in quality among the 45mm f4 lenses; it is just pot-luck whether you get one which is sharp across the range of turns noticably rather soft. I swear my 45mm is a gem!
I can certainly believe it was a solid performer. Some years back, I was building a P67 system by buying complete kits, testing and culling the duplicates. More than any other system, I found great variability on the same lenses. The 135 macros seemed to vary and the 105 seemed inconsistent, too. The 165 was solid but the LS seemed to vary....? The good examples of any of the P67 optics were very, very good and could stand with almost anything. In those days, it was easy to sell off these lenses and I recall always being money ahead by buying groups of items when offered and selling off the culls by piece. I use rangefinders these days for wider duties and haven't seen the sort of performance variations that I do with the P67 glass. In actual use, off a tripod, especially, there are many variables affecting quality than hair-splitting glass differences, though!
As I write this, I recall how different various tripods would behave with the big Pentaxes. Some rather heavy rigs that one would expect to work well just seemed to vibe at the wrong frequencies. I learned quite a lot from mounting a laser pointer to the camera and inspecting the negatives using my own and borrowed pods and even spent some time in a photo shop, using their demo rigs. MLU took care of much of it but even then, the shutter motions would induce odd motions at certain shutter speeds.... I guess that's enough hijacking of a thread for now!