I'm not Land Rover Ninety smart, so forgive me, but on the early Defenders was the capping galvanized like on the Series trucks? When I first bought my Series the cappings were painted black as well and that was quickly done away with.
I've seen several Series trucks with painted capping and that's no big deal, however on a Series truck the bulkhead is steel, and a hugely expensive piece to repair or replace. I don't know if the Defender is the same or not, although I don't see why it wouldn't be for that early a year. If I were going to look at the truck though it'd be something I took a magnifying glass to though.
Either way, very nice early Defender if you're looking for one.