Strange adapter plate IMO. The hole through the plate bypasses the cooler, so there would be less flow restriction I suppose. Maybe it's a rather restrictive cooler and they need this hole to avoid oil pressure drop? Possible the hole even has a thermostatic effect, with more oil going through the cooler as the oil wams and gets thinner?
The big bolt is a bit of a mystery. As long as the holes line up to all be inside the actual filter - between the end seals - with the filter in its working position, it should be OK. The standard bolt includes a pressure activated filter bypass to allow oil flow with a clogged filter, I wouldn't want to do without it: does your bolt have this valve?
Personally, if it fits at all on your engine - I forsee trouble with the frame tube and exhaust headers but it might be OK - I would try plugging that hole by attaching an aluminum plate on the engine side with a couple of small screws, and then check the main gallery oil pressure. If it's comparable to the stock filter-only pressure I'd run it like that. If it's much lower I'd unblock the hole and use it as is.
The best approach IMO is to get a Terry's or similar adapter and use braided oil lines that you can fit to suit your bike, the cooler looks to have standard threads but the adapter has those plate things. The cooler should be fine, if it is too restrictive you can drill a similar hole through the separating plate easily enough - or get a new cooler too?
