What is a KÖRUNG

The Körung is an advanced breeding suitability test for the very best Rottweilers who have already achieved their ZTP. To apply, the dog must have an eye color of 3A or darker and their mouths must be at least fifty percent dark. The dog must have received conformation ratings of SG or V at least three times by at least two different judges.

Males are required to be titled through Schutzhund III and have attained an AD. Males must be at least thirty-six months of age. Females must have at least a Schutzhund I and be at least thirty months of age.

Rottweilers that pass this test are endorsed for a two year period. At the end of that time, the dog can take the Körung test again and must additionally provide proof of correct progeny. If the dog passes the second time, it is endorsed for breeding until the age of nine years for males and eight years for females, at which time the dog is to be retired.

The Korung, if passed is on the pedigree as Gekort, is the second, more advanced breeding test. It is not required but any dog or bitch that passes the Gekort is a more valued breeding partner. This test can also be taken again if the protection phase is not passed the first time. The requirements are more strict as far an conformation goes, requiring darker eyes and darker mouth pigment than the ZtP does, and the requirements in the protection phase are harder to fulfill.
Any dog entering the Korung must have a SchH III title and a bitch must have a SchH I minimum.
On paper you would believe that any dog that meets the minimum requirements to take the test could easily pass. But it is a tough test to pass.
A Körung is an event where breed survey/s are done. In order for a dog to try for a breed survey, it must minimally hold either a SchH 1 or an HGH title. It must also have completed the AD, the Ausdauerprüfung (a 12 mile endurance test) and have received at least a "G" (meaning Gut, in English "good") or better in a conformation show, and have hips and elbows cleared by one of the organizations that does this (the SV a stamp program, OFA in the US, and others in each country). When a dog passes a breed survey, which begins with a proscribed protection routine that it must pass first, then the Körmeister (a special certification held by only a few people) will use a specified form to fill out describing the dog. This report is known as a Kör report and you can find one by looking at this site under certain dogs. Here is an example in German:
"Übermittelgroß,mittelkräftig,sehr gutes Gepräge.Normaler Wiederrist,fester Rücken,kurze Kruppe,gute Winkelungen,gerade Front.Richtige Brustverhältnisse,vorne erg.hinten geradetretend mit guterSchrittweite,Ellenbogen müssen geschlosener sein.Sicheres Wesen,TSB ausgeprägt:läßt ab."
Not all GSDs have participated in a Körung, and just because one participates does not mean the dog will pass. If the dog fails the protection routine (*consisting of attack on handler out of the blind and the courage test, sometimes called the long bite), then the dog is immediately dismissed and must wait one year I think to try again. Once a dog has completed two breed surveys in the proper time frame, it is given the LEBENZEIT designation, meaning it need not ever do a breed survey again. 
Two classifications may be awarded by the Körmeister when he/she performs this inspection. One is called KKL1 and the other KKL2. This abbreviation stands for Kör Klasse 1 or 2. Dogs awarded KKL1 are "recommended" for breeding, and dogs given the KKL2 designation are "suitable" for breeding. Often the difference between getting a KKL1 vs KKL2 is based on some minor fault, such as in dentition, or structure. Sometimes it is based on some other factor, including conformation that is not quite correct, and yes, I suppose there are judges who, for example, simply will not give a KKL1 to a dog coming from working lines, but I have not had this experience.
The coat of your pup will change with time until he is several years older, but in general, what you see by a year old is what you will end up with.
If you are in the US, x-rays may be submitted to the OFA for preliminary readings as early as 4 months old. Permanent ratings are not given until x-rays are submitted at or after 2 years of age. in Germany, the "a"  stamp may be applied for as early as one year, and in some other European countries this is also the case. So whether one can get a certification at one year of age depends on what country you are in or what certifying organization you use. One can, for example, submit x-rays to the SV in Germany even though one lives in the US.