Silly question. What type/size screws retain the rear speakers to the speaker grilles in 1989 GT hatchbacks? My old speaker grilles were apparently modified to hold speakers in from the front, and now that I've purchased new grilles I am not quite sure what screws held the speaker on the grilles via the 4 retention tabs on a stock configuration. Couldn't find the screws online anywhere for attaching the speaker, just for attaching the grilles to the vehicle. Thanks!