Still searching for a "Pentagon" shaped inlay.
But I did recall that some casinos have used "faux" shaped inlay designs. Actually, they're all round, but in the inlay design itself, they have created a faux shape (cog, hex, etc.)

The Missouri casinos seem to have done this quite a bit (and in addition, the first / oldest Missouri casinos used actual inlay shape varieties too).

Examples: Real inlay shapes --
http://chipguide.themogh.org/cg_chip2.php?id=MOSLPO&v=1638525733
http://chipguide.themogh.org/cg_chip2.php?id=MOCACA&v=2983762034
http://chipguide.themogh.org/cg_chip2.php?id=MORIR1

Examples: Faux inlay shapes -- (but still no pentagon)
http://chipguide.themogh.org/cg_chip2.php?id=MONKHA&v=2498251371
http://chipguide.themogh.org/cg_chip2.php?id=MOCGCC&v=2479814394
http://chipguide.themogh.org/cg_chip2.php?id=MOSCAC&v=3343535354
http://chipguide.themogh.org/cg_chip2.php?id=MOKCAC&v=600313347