@Zincy
Hm… The problem with heraldry are less the symbols and the colours, but the arrangement and design. But of course I understand that the family name is private. A red hand is usually an indicator of a baronate. Perhaps the origin of your family branch.
The silver dagger is indeed rather unusual for a coat of arms. It could indicate a possible officer’s license, but is rather unlikely. It could also have been added at the request of the founder of the coat of arms. Without knowledge about the exact image of the dagger, no clear statement can be made here. Crescent moons usually stand for a veneration of Mary, the mother of Jesus.
But before I give a wrong interpretation, I cannot conclude any noble origin without exact knowledge of the coat of arms. It could also be a so-called citizens’ coat of arms (Bürgerwappen). These became more and more popular in the course of the emancipation of the (wealthy) bourgeoisie. Citizen coats of arms were first used in the 14th century. They had their prime in 15th century and were still in the 16th and 17th century generally widespread.
Sorry, but I can’t help you with more information so far. :-)