Iron Case/Tail 833OD Output Shaft Seal Question

Okay, I need to really look into this [obviously] before I put this transmission into my car in the next month or so. As the title of this thread states, I have an iron case 833OD and I am confused about its output shaft seal. Currently, the trans looks like this:

The splines are exposed on the tail shaft, and that doesn't seem right given that every picture of an 833 that I've seen has an external output shaft seal that slides around the slip yoke.
I ordered a seal from Passon, and the piece showed up as I expected.

My question is if this is the right piece. Based on the first picture and the picture below, it appears that their appears to be some degree of seal provided by the existing piece that is pressed into the tailshaft housing from the rear.

Do I press this output seal in behind the thing that is in there now? It seems like it should fit, but I don't want to go hammering something in if it's not right. What's more, I've attached two pictures to highlight two specific holes/notches in the seal. If this is to be installed in my transmission, do these holes have any importance with regard to orientation for drainage/ventilation or something?



Help is much appreciated on this one guys!