May well be an earlier ARB then, I had one that I fitted to my 10-spline RR diff in about 1998 and rebuilt it not long after and I'm pretty sure the seal housing was the same as the one in my Defender when I bought it that needed repair with every second tank of fuel- a different seal housing attachment to the one shown. The engraving on the carrier housing suggests to me that it isn't a cheap knockoff.

