Great Joel. I always say Warranty Book, I guess because I was told "Wartungsheft" roughly translates to "Warranty Sheet" and I think it should be in the Warranty Book, why the Maintenance Book? Maybe to make it easier for people in the shop to locate it, not sure.
Is the pipe you're talking about on the front of the engine? That's supply, not return, I think you'll find there is only 1 kind available now anyways. The o-ring you need is pretty common, we usually just asl for "a gray o-ring", they use it on both places on the engine where the coolant pipe enter, both on the water pump and the left rear corner of the head.