my moving target guide had a similar problem with the broken plastic.  i tryed araldite but it only held for a few games, i repaired mine with a $2 L bracket from bunnings, i only had to redrill one hole in the L bracket.

mine didn't split down the center like that, the tab at the top where you put the screw to hold it to the play field broke off so there wasn't much surface area to glue


looking good