No slot per se, but the kickplate is routed along the top edge, which has the lip resting on the top of the routed portion and against the back.
That is, there is an L shape when looking lengthwise down the top of the kickplate and the lip rests in the angle from the top right.
If that doesn't make sense, I'll take a picture tommorow, but be warned that the original kickplate on my Galaga has water damage and has come apart, awaiting replacement once I haul my table saw out. I can't even get good meaurements on the routing.
Cheers.