According to the rumors, word has that it both the HTC Sailfish and Marlin handsets will be of different quality. The rumors are claiming that the Marlin will feature the same build quality as the HTC 10, while the Sailfish handset will be a combination of both metal and plastic. We have heard the rumors that the Sailfish will be the smaller handset of the two, so perhaps the choice to go full metal for the Marlin could help advertise it as being a flagship phone.
It could also be a sign that the Sailfish phone will be cheaper. Interestingly enough an earlier rendering revealed that the Sailfish could have some kind of glass build on the back of the phone, an odd choice if the rest of the chassis were to be made from plastic and metal. However a recent Marlin rendering certainly looks like the phone could be made from metal.
In any case this is probably best taken with a grain of salt, but if Google’s timetable is still on track, we could be getting all the official details in the coming months.