I was looking to buy an SMC-A 50 1.7, so I can use it on my P30T in the program mode.
The "perfect condition" one that showed up had a broken aperture dial. I could only turn it from 1.7 to 8, it would not go past that.
Then a little deeper dive research shows this to be a common problem, they are poorly made at least in the aperture dial and break like this. So, it looks like it's either a 1.4 or be happy using it with my non A lenses.