Rear Speaker Boxes

[NiftyNev]

I realize that this may be a totally dumb question but...... How do I change out the rear speakers? I have the Pioneer 4 inch ready to slot in and I presumed that I just took out the 4 plastic looking Allen key fittings on the front of each speaker box to access the speaker itself. They do not seem to want to turn and I am in danger of stripping the the Allen key holes of the plastic bolts.
Are they just for show? Do I need to access the internals of the housing from from the underside of the boxes? Please help and thankyou

[NiftyNev]

Sorted it, finally. Took rack off, Unscrewed the rubber dampeners and that accessed the internals. Sorry for wasting peoples time It just didn't make sense to me to have to do all that.

[ghostler]

Those molded dummy socket heads in the front fooled me, too. After a little clean up with a sharp knife to remove the knurls I created, I'll need to get some touch up paint to hide my damage, so you are not alone.

[krasmu]

Don't feel bad guys. this is a common problem. You are not the first to try to remove those screws and mess them up. Ask me how I know!