If it has an octagon barrel it is not a "trapper" type. This term is usually reserved for Model 1873 and 1892 short barrel carbines. Carbines, and hence trappers, never had octagon barrels. So I am pretty sure you have what would be termed a short rifle. The cresent butt plate, no ring, buckhorn sight, and octagon barrel are all consistent with short rifles. The photo is of a short rifle with a 22 inch barrel. Standard length was 24. Shorter barrels were available at the time of manufacture. There were only 2252 rifles made with this length barrel out of over 5,000,000 1894s!! So they are very rare. Often a barrel has been cut down in the past. You can tell the difference by noting the distance from the end of the barrel to the magazine retaining ring. The front of the ring should be right near 3 and a 1/2 inches from the end of the barrel. Anything shorter is a cut down barrel.
Original short rifles are slightly more valuable than a standard rifle in the same condition. The .32-40 was not produced in large numbers and made up just 11% of the rifles prior to 1905. Send a few photos. There are still some unknowns that limit an educated guess.