There seems to be an extra pin or something in the drawings 5H2176 - that doesn't seem to be in the picture of 4H8765 unless it's behind driver pin 4H8766? Does the small protrusion on 5H2176 fit into a recess in the track pin?

I'm going to take these drawings down to my guy and get him to make it. I have a 5U where those pins are loose, and a 3J and a 4U that I haven't moved the tapered plug pins from so this would be just the ticket

(Sorry for hijacking the post).
I have a question for anyone that knows how to interpret the drawings. On the drawing for 5H2176 with the tapered protrusion, the end view shows a diameter for the tapered piece of .990 and .988 (so 2 thou difference). Is that the diameter at the gage line indicated, or at the tip (minus the chamfer)? I think it's the gage line which means from there, it tapers thinner at 5/8 per foot.
For the 1/4 between the gage line and the 1 1/2 in end of the main shaft, does the taper continure for another 1/8 until it enters the radius? When it says "do not center this end", does it mean to not put a "divot" in the end for like a Morse taper?
For this tool, since its diameter is 1 3/4, it's not intended to fit into the sleeve, so I'd guess that it is intended for installation of the pin, not removal?

For the 4H8770 which is the tube that the pin fits into, it doesn't show the diameter, but it obviously needs to have an ID bigger than the driver that fits into it. How much total clearance would folks give for the ID, given that the 4H8766 drawing seems to show a 1.210 to 1.220 diameter if I'm reading it correctly? Would 005 be enough to slide easily but not wobble? The tube looks to have a 1/8 wall thickness and I'd think a piece of DOM would suit?
The actual diameters I'd need to modify to suit the D2 pins which are 1.125 whereas it looks like the 17A has 1.250 pins but the clearance could probably be the same.
I'll take measurements from the D2 this weekend to adjust the drawing dimensions as appropriate.

Dieselholic, could you tell me what the text says about the use of the tool. Is the 5H2176 just for installing the master pin, and does the pilot fit in a tapered plug pin? __PRESENT