Thanks @fyud. Yeah I still have those and I think that's the Gen1. After some digging from the reviews I could found online I believe the only generation they were using aluminum for the network exterior is Gen1, after that they are all made by acrylic.
@dave_b yeah I actually am not sure if acrylic finish improves the performance. To me the aluminum finish is aesthetic better than plastic. But again it's just my opinion on the look along, not sonically.