Manuscript Am B 340 contains three pieces that are generally believed to be composed by Karges himself. These are a Fantasia, Capriccio (though Karges composed only the first half) and a Præludium. The pages in the manuscript, immiadetely following the pages on which Karges' Præludium is written contain another Præludium. In style and atmosphere this second Præludium is very much like the first one. It is therefore tempting to suppose that this piece was written by Karges as well. He did however not notate any intitials, so there is no way to be certain. Unless, of course this piece is known from another source, but until now i have not found another reference to this piece.
Score available here: http://partitura.org/index.php/wilhelm-karges-praeludium-d-moll