I'm not sure this is the best place to ask. But, I've tried to gather all the information I can on this knife and am curious if anyone could provide any more details.
Here is my Cattaraugus Teardrop Easy Open Harness Jack in (what I believe is) Ebony. Propeller shield. Spear point, not a clip. 3 5/8"
I've seen that the way the numbers work out, my knife is likely a 2xxx6 or 2xxx7, but I think it is ebony. I've seen mention that a bolster number of 4 is either unknown or easy open with 2 bolsters. And that a bolster number of 1 is one bolster as is seen on my harness jack. I'm inclined to think it's a 21xx6, despite the easy open. I am lost on pattern numbers though. I also didn't see any abbreviations that seemed to fit.
These knives look very similar to mine. Both are ebony. One bear head one not. One has propeller shield. And, one is spear point.
Edit: It looks like the image didn't work in the quote above despite me seeing it when writing this post. If Charlie doesn't mind, I'll add my screenshot of it above.
I swear I saw Charlie post three catt hj's in a triangle, all had disc shield, two were pick bone, and one was ebony. The ebony was very similar to mine, but different shield and no easy open. The pictures weren't loading for me though. (OMG, when I quoted this it brought the picture back! I screenshot it so I don't lose it.) ... I now see that the ebony hj of Charlie's also had rat tailed bolsters and mine does not. Mine does have an identical punch and spear though, which makes me inclined to believe mine is more original.
I found it odd there is no pattern number stamped on mine. I also noted that both implements are tang stamped. I wonder how old this knife may be and if it is indeed all original. I believe the same tang stamps were used from 1886-1963, which makes things tough.