Supermicro's C7Z87-OCE board had no PS/2 port (although their regular C7Z87 board did). But their newer C7Z97-OCE board does have a PS/2 port. Any reason why they got rid of it and then brought it back?
All I can think of is that sometimes it happens that it's impossible to enter BIOS with some kinds of KBs, specially wireless ones so using PS/2 KB may be only way. It's possible that they realized that and introduced it again in next version. Many MBs have also combined KB/Mouse in one port. Manufacturers also love to cut costs and would remove anything they don't consider important but also may change their minds. Most of them make many revisions of same MB.