No, that's a short one they put on the later 68's. 

That's to bad, because that is a great price and on the pipe. Somebody should grab it.

Looks to me like that ebay one has something "homemade" for an exhaust outlet?

Back in the day, my brother made one in metal shop just like that one for my 69 AT1.
AND wrong year pipe. A 72/73. otherwise yep, nice pipe.

DT1 Dave- what is the VIN # of your bike? Just curious. Mine (1717) has the small outlet exhaust, but the insert is shorter. I was considering making one to suit if I needed it to be "correct".

Agree on the comments about the eBay pipe. I believe that is for a later year, although it would almost certainly fit and work.

I have to wonder about the '68s. They had so many changes (upgrades??) initially that it seems difficult to really conclusively state that 'this one' is "correct" and 'that one' isn't. The bike I am working on actually had the larger outlet muffler on it when I purchased it, but swapped it out for a small outlet when I spotted one. I suspect the large outlet pipe either gave better performance, or made cleaning the insert easier. Does anyone know?

Don't know for certain , but I suspect it was for better performance .
The main jet increased from # 150 to # 160 , so that also suggests
increased performance .

All '68 DT1's had the small diameter outlet exhaust pipe.  Early '68's (I believe up to VIN #13000 when several other parts were updated) had the longer stinger with a bend in it.  My understanding was that the change to the shorter straight stinger was due to the long stinger bending around the shock and either breaking off or pinching the end of the exhaust outlet when the bike went down on the right side.  In '69 they changed to the larger diameter outlet but I do not know why exactly this was done (performance or ease of cleaning).  

Apprecite the pics Gersh. The pipe I have has the short stub. My plan is to eventually get the bike to the point of running, and maybe go from there.