Idler arms early a vs 67 up cars

I have heard of people modifying a 67 K-frame to take the 68-up idler, but there was a lot of skepticism on the forum as to whether it could be done accurately enough to maintain perfect geometry. The response was, with plenty of 68-72 A-body K-frames available, why not just swap? I don't know how different the 65 K-frame might be, dimensionally, but if the idler is the same exact unit as the 67 idler, you would think it could be done. I am not sure if it is worth it, however. The bayonet-mount idler is perfectly adequate so long as it remains sufficiently tight. The problems occur when the nut is too loose and it can move around, destroying the tapered hole and ruining the K-frame for all intents and purposes. Even in these cases the idler arm itself is usually fine — it's not the problem.