Sorry for the flippancy.
No, the PC doesn't have that problem, and it's not related to the position
relative to the power supply, other than that being a convenient way to
identify it.
I have no idea why IBM did that. Perhaps intending it for some
"special" card that would need it, such as a coprocessor? Maybe Tony
could explain why somebody would design it that way.
--
Grumpy Ol' Fred cisin(a)xenosoft.com