I reposted the fancy bolster Verlangerungsmesser, marked "PATENT 19946" on the blade because I just found the 17, Nov. 1882, Patentschrift for the "PATENT 19946" on the blade.
The bolsters do not have the fine grooves as shown on the other fancy bolster Verlangerungsmesser examples.
NOTE: "This knife has no button or visible lock and comes apart at the plain bolster side". (This is probably what was patent).
This new information was found on "The Blade Blog" site by Ulf Ahlstrom. This is a great site and here is the link:
http://thebladeblog-ulf.blogspot.com/?view=flipcardIt sold on Ebay for $747.79 with 13 bids on Mar. 6, 2022, even though there was no sheath and the blade had rust marks and the tip was damaged.