Very old saw vise

Last weekend I went to some garage sales on a whim, hoping to find some old wood working tools.
One of the treasures I found was this oak saw vise. The gentleman who owned this antique explained that when he and his wife bought their house in Germany this tool along with others were inside.

The large wing nuts look rough cast which should help me date it.(I hope) The number 5 is stamped into the wing nut( I don't know how this is relevant). 5 could stand for a bolt diameter however, the bolt measures 10mm. One of the bolts has a "F" cast into the head.  I am guessing that this was made by a German woodworker.

The vise did see active service as evidenced by file marks going transverse on the top where the saw is clamped.  One of the clamping blocks has been hollowed along the length to allow a tight fit at the top where the saw blade sits.

Length : 12 11/16 "  (32 cm)     Width 2 7/16"  (  6 cm)    Height 4 3/16"  ( 10.5 cm)