Recent photographs and information have come to light detailing the possible adoption of the Heckler & Koch G28 by Turkish special operations groups. Specifically the Turkish Combat Search & Rescue (Muharebe Arama Kurtarma) component of the Turkish Air Force has received the rifles possibly as early as 2014. From what we understand the CSAR component might have got them from trials done on the G28 by Army commandos but due to the political situation between Turkey and Germany over the refugee crisis (among others), the supply might have fallen through. The image above is actually from some of those trials.
From the photographs that have surfaced online, it appears that the rifles have come complete with their full product package of the standard configuration with the NATO STANG 4694 rail system (essentially a MIL STD Picatinny M1913 rail) mounted with a Schmidt & Bender 3-20×50 PMII, with an Aimpoint Micro T1 as a close range option, however it appears to lack the Rheinmetall Soldier Electronics LLM-225 laser aiming module that H&K offers as standard on the product page.
Among other recent small arms in use by the Turkish CSAR is the H&K 416A5 in 5.56x45mm NATO. Ironically, in Turkey’s quest to standardize a locally made version of H&K rifles, the special operations components aren’t buying in entirely and are simply opting for the original rifles from Germany themselves.