Yes. It works in 14.04.3.
$ lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 14.04.3 LTS Release: 14.04 Codename: trusty
$ fglrxinfo display: :0 screen: 0 OpenGL vendor string: Advanced Micro Devices, Inc. OpenGL renderer string: AMD Radeon R9 200 Series OpenGL version string: 4.4.13374 Compatibility Profile Context 13.35.1005
Yes. It works in 14.04.3.
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 14.04.3 LTS
Release: 14.04
Codename: trusty
$ fglrxinfo
display: :0 screen: 0
OpenGL vendor string: Advanced Micro Devices, Inc.
OpenGL renderer string: AMD Radeon R9 200 Series
OpenGL version string: 4.4.13374 Compatibility Profile Context 13.35.1005