Originally posted by Thorgrim
Of course. There's no restriction to the mounting of weapons except for the 15 limit. And the requirements of each weapon, but that's not the point.
Common sense still applies though. Avoid mounting ammo-dependent weapons in the head and engine location. If it's a support titan, try to install your main weapons to the upper section of the titan (you'll probably want to be crouched for long periods of time). Having weapons installed to the arms and head is usually best, especially if you're planning on going CC/charge/DfA. Excessive amounts of ammo (especially in a single location) is asking for trouble.