Here are three Double-Ended Bullhead Jacks, or Moose, knives by The Robeson Cutlery Company.
First is a Swell-Center Equal-End 622187 pattern with nice brown jigged bone and an escutcheon shield. 4" long.
The next two are Terrier Cutlery Company knives, made by Robeson between 1910 and 1916. These two knives are about "mint", and both came out of a closed Mid-Western hardware store via Ebay.
This 243622 Terrier is 3 1/2" long, has brown jigged bone handles with an oval shield. There are salesman sample numbers on the back of the master blade.
The master clip is crocus polished on the mark side, but glaze finished on the back, as is the secondary spey blade.
This little knife is only 3 1/4" long. It has no pattern number on it. It is, however, a double-ended jack, so it is a "Moose".
It has nice brown jigged and grooved handles with an oval shield.
The blades are sheepfoot master and secondary spey. They are crocus polished on the mark side and glazed on the back
Robeson also made a 4 1/2" surveyor pattern moose in bone and ebony. I do not have one of those but I do have photos of one somewhere.
