Robert…the air box mount is white rubber on your bikes? That would be the lower front mount? I hadn’t heard or seen that one yet.

Yes, both my 68 & 70 had white on the lower air box mount and were deteriated so i'm pretty sure they were originals. I installed white back on both bikes in that location. My 68 doesn't even have the same mounting hardware as my 70 or as the parts schematics shows for the rear fender back mounts. It used the same black gromments for mounting the lower back fender. I have seen 2 or 3 different fenders and mounts for the 68 DT1's. Mine just takes a black rubber grommet in the fender and a 25mm long  6mm bolt, nut and large flat washer under side of fender. I have seen some with hardware like my 70 DT1 has.

Installed my complete front end, headlight bucket and gauges plus both fenders today. Starting to look like a bike now. lol! 

Does your rear fender mount like this?  

Robert…my taillight mount is the same. I believe you install a white rubber and spacer in the front of the taillight bracket and so they mount back to back on the fender using that long bolt you mentioned. My two rear fender mounts use the mounting hardware like the parts diagram. Motodad on EBay sells an exact kit. 

Yes, taillight bracket has a white grommet too and they stack on top of each other. I was referring to the rear mounts for the rear fender. So yours has the mounting hardware like my 70 DT1 has. Most do. My vin is DT1-03XXX which i consider low production. Wonder when they changed the rear fender mt design? My 68 and 70 fenders are different including the width.

I know of at least two different 68 fenders because I have them. But they mount the same. Early ones have different bracing underneath back at the taillight area and those early ones don’t have the wire harness loop spot welded to the left side. They don’t have the loop at all. NHSteve and I have confirmed those differences based on original paint fenders. My bike with the early style rear fender has the 6mm bolts for mounting the gas tank. Later ones came with 8mm bolts.