My 40 year old original gate doesn't fit quite as snug as that ute one but that could be more to do with the Freeway camper that was bought and used with/on the ute from new back in 1975, or even the bikes (think ramps on the tailgate) and heavy crap I've I've loaded on it from time to time over the last 17 years I've owned it or the fact I do like to drop the tailgate and sit my fat 100kg+ rrrs on it to have a cuppa when I'm travelling too...

Is there much play in the hinges or do you reckon you might be able to "adjust" the holes/bolt position so as to bolt-up closer (tighter) in?

It may well be that the tailgate that was being used as the original template for the repros had bend in it a bit too or maybe the tooling is a little worn nowadays?