My father in law has some bayonets and I am trying to find out about this particular one. The info I've collected so far that this bayonet is a Seitengewehr 98/05. German stat of issue are Prussia and Wurttemberg. The date of acceptance is 1915. The bayonet is 19 1/2 inches long from end to end. But I do not know what "RG" stands for on the spine of the blade. Is this correct? Here are the pics. Also what would be the value of this bayonet?