The outer row of bolts have been shown to bend the head, prising the head and block apart around the combustion chamber, they actually do as much harm as good.
As stated, Land Rover supply a modified gasket without the holes for these bolts. It is quite possible that one bank has had some rectifiction work so only one head came off. For example has it had any new valves?
I tend to agree with 'if it's not bust, don't fix it'. If it runs sweet and does a good compression test then it meets the major criterior for a healthy engine. Oh, and if it looks clean inside it may be that it's been looked after, ours looks the same after about 60,000 miles! Check to see if both heads are skimmed the same, on the front of the drivers side (I call it the RHS) head is a small square block with a hole in it, if the head is skimmed the hole is nearer the bottom than the side, this is a witness! It's on the back of the LHS because they are the same head.
I've seen the early heads fitted to later engines and vice-versa. It really shouldn't be a problem.
DON'T, what ever you do just add the 4 bolts at this stage, you risk disturbing the gasket and making things worse! [-X