I have an early build (8/01/68) 69 Dart GTS. The timing marks cast in on the passenger side of the timing cover would be correct for my early build 69 Dart GTS with the 340. I'm actually watching that one mentioned above on Egag.

Also...the lower piping on the 68-69 340 water pump goes to the drivers side not the passenger side.

So, in this Egag auction it has a correct 68-69 340 water pump, but an incorrect 68-69 340 timing cover. If the timing marks are on the same side as your lower hose it might be hard to see.

Egag water pump & timing cover