There will be four different mounting options for each weapon. Normal and right angle mounts are fixed to the direction they are pointing at. Then there are gimbal and turret mounts. Turrets are able to aim at targets in a semi sphere area. Turrets are more expensive, require more power, more space and they do suffer from a gimbal lock around the zenith, that is, they have some problems if the target is exactly above them. Gimbal mounts are like normal mounts, except they can rotate a bit left and right and up and down around the starting direction. They do not require a bigger mounting spot like turrets do but are more expensive than fixed mounts. They can only be mounted on forward mounts however, right angle mounts are always fixed to the direction they are pointing!
Gimbal mounts help less maneuverable ships to target faster ships and they also provide nice automatic gun harmonisation (https://en.wikipedia.org/wiki/Gun_harmonisation) with adapting convergence point, which is needed against small targets. In the video the first corvette has beams with fixed mounts. The second corvette has gimbal mounts and it hits the small fighters much better.