Just to clarify, youre trying to remove the whole 2lt engine and replace it with the 2lt2? And trying to figure out how to hook that up? Or are you trying to swap heads like the OP was? If youre trying to swap heads, pull the valve covers and see if they are both bucket shim or if one has rocker arms.
If youre trying to swap the whole engine, and youre 2lt injector pump is good, you should have no problem pulling the old injector pump off and putting it on the new engine. Make sure you adjust your timing properly if you do that though (easy when the engine is out of the truck).
If you want to keep the new injector pump I think the 2lt2 should still be mechanically injected but you should post a photo and part numbers off the injection pump on the 2lt2 so we can see what sensors etc it has. If it has spill control valves and a crank position sensor etc like the 2lte it will need an ecu to run it. Other sensors you might be able to ditch. My 5l has a weird pump that has way more sensors than its supposed to but im able to run without the tps, and rpm pickup or a proper feed to my tcv. Check and see what the timer cover looks like (left side of pump towards the front). The mechanical timed pumps and electric timed pumps seem to have different timer covers.