Yes, it should be decently snug ie: not rattling around or falling out. I would focus first on the latch. Take the clear panel out and look up where the clear panel insert handle once was. There is or at least should be a plastic latch piece. It is passive with no mechanical function. If it gets pushed up you can gently pull it down a bit with your finger so it catches better with the clear panel. Be very careful however as it is plastic and will break with too much force. The clear panel *should* snap into place with this latch leaving no gap. If your panel is loose and is falling out, the plastic latch bit may be pushed up into the case too make decent contact or broken off.
In regards to them being different, yes I can confirm that there are differently design clear inserts for different PMG5s. For example, the insert in my A1047 does not fit into my A1117 as it has a bulbous part that bumps into the intake dual fan housing blowing air across the dual core cpu & heatsink. Conversely, while the insert of my A1117 does fit into my A1047, it does not fit correctly, leaving a gap between the differently designed intake dual fan housing (whoch blows across the dual CPU+heatsinks of that box) which I assume would lead to improper air flow patterns and ultimate thermal failure. If I was in this situation, I would try to seal this gap by sticking a dense piece of foam carved out to fit in that space to help seal and maintain correct air flow through the case & over the CPUs until I can get a proper insert.
Another thought I had was that perhaps your insert is warped or the case was dropped and bent - this make sense to me as it has no door. These doors fit extremely snugly, so any drop or deformation due to impact could make it so the door wont fit, hence why it was left off in the first place.
No worries though if this is the case. I personally really like how PMG5 of any design looks with just the clear insert showing all of its deliciously engineered guts. If this was the case and a latch adjustment did not fix your gap issue, Id fix it by using some clear packing tape to hold it in and to seal the gap. Need to get at something? Just pull it off, do your thing and re-tape the top bit. The bottom of the clear insert should be flush either way as all clear inserts to my knowledge have 3 taps holding it snugly in place. Kinda ghetto fix but it would work I think. That vs the possibility of having to try and bend back a warped case just sounds bad to me or the other alternative - dumping all the guts into a cleaned out g5 donor case - woof, just as bad sounding to me.
Another cool opportunity with just the clear panel on would be to invest in a neat multi color LED strip of two - yanno the ones that are like 15 bucks shipped USD with remote? Man custom LED lighting would look really sweet glowing off the aluminum case & refracting off that clear insert. I'd love to see a pic of that. Heck maybe Ill do that to my A1117 sitting on my desk.
Either way good luck to you and congrats on your new G5 box
