marineland versus all glass aquarium tops

[StuG]

So, I am going to need a new glass top/canopy/hood/whatever you want to call that bit for my 55g tank.
Of course as I got this tank for free I have no idea who it's made by.
I've read conflicting reports about whether the glass tops are interchangeable or not, and don't want to go ordering one until I can at least try to get a more definitive answer.
So, anybody have any idea if they are both pretty much the same thing for a 55g aquarium (with center brace), or if indeed they are made quite differently?

[ilostnemo]

go to your lfs and take the measurements of inside lip to inside lip to them they can order you one to fit. and they are made differently.