No need to argue about the pins. If you think that the problem is the socket, you only have to disassemble it and / or check the solder joints. I don't know other way to check it.
I still think you could try removing the bracket from the expansion cards to make sure they are inserted correctly.
For example, VLB cards sometimes need force to insert them well into the brown part of the connector and if the motherboard is bent they will not fit correctly.