Cleat question

I had something similar on my Shimano T30 shoes. Not sure if it is the same thing, but I removed the insole, and under the ball of the foot area there was a small flap that opened up so you could remove the metal mount. Maybe your shoe is different, but it's worth a try...

That's where you would attach a SPD cleat. You can try taking it out, but I'd see how the foot bed feels without it as you may effectively create a depression under the ball of your foot. Leaving it there will hurt nothing.