Ah the question of hull insurance happens to be my speciality....
Under the main hull and liability policies held by all airlines there are exclusions for War, Terrorism and allied perils.
However, almost all airlines also purchase a specialist "Hull War" policy which covers on War, Terrorism and allied perils. If an airline operates aircraft leased or financed (rather than outright purchase) then this policy will be a requirement of the lessor or financiers.
I know that SirLankan's aviation insurance is placed via Willis Aviation, a large London based broker, and the current "reserve" placed on the claim by insurers is US$450m.
There will be a policy deductible (excess) which will need to be borne by the airline.
It was also noted in this weeks Travel Trade Gazette, that as a result of the loss of these aircraft, SriLankan is extending it's retirement policy and may well be undertake some compulsory redundancies amongst all staff.
Therefore, I am afraid it is not good for them at all, especially as it is unlikely they owned any of the aircraft, therefore the money received from insurers will all go direct to the aircraft owners, leaving Sri Lankan to go out and negotiate new leases if that what they require....but bear in mind the lead time on an A330 is currently c12 months.
Oh, as a result of the incident "War Insurers" are charging all airlines (inc SriLankan) an additional approx US$100k per flight into Colombo....hence they don't seem to be rushing out to find lots of replacement aircraft at the moment, until they either set up new routes avoiding home base or any potential troubles subside once again.