the seals are outboard of the bearings. the only way to get them off is to press off the bearing. they have a rubber coating on the outside, no o ring. so i would say pressed in. but they are leaking out of the lip. nothing is loose. the fill is on the third member.
Not sure about the Currie housing but, the Versaille housing I use, has an inner seal, an O-Ring on the bearing (Moser Axles), and an outer seal that would not seal much of anything it's more of a dust seal. I asked Moser if I should bother putting the inner seal in, and they said definitly yes!
The tapered roller bearing style of seal, seals on the outside of the housing, so there is no way to install an "O" ring. Unfortunately, the tapered bearings need the oil in the diff for lubrication, so there will be oil in the vicinity and there can be some seapage. Check the oil level and only fill to the fill hole, more oil will cause problems. The best thing to do is get everything clean, and then smear some silicone arond the circumfirence of the seal where is meets the housing. I build circle track 9" rearends for customers with the tapered roller bearings and leakage is a common issue, especially on the right side axle tube. Silicone usually stops it.