Yes there is a metal guide on the left.
The reason it has broken is not that guide nearly every WH20 I have seen had broken ramps they cop a beating once the targets move a bit the ball can impact the front edges of the ramps.
That is why the reproductions are so good heaps thicker and guaranteed for 12 months (better check with Greg but I think that was the case)  They also come with new ramp flaps already riveted to them to save you the dramas