I was playing World of Tanks recently. I was sailing my Exelsior, and spotted an enemy Hetzer sailing broadside on, likely in transit. I fired my gun and landed a nice hit in the Hetzer's upper hull.
It's just another Hiei, your current one won't be affected. You'll have two and they can start a garage band together. Personally, I'm glad that it is Hiei and not some other ship, since Hiei was the only Kongo that needed the tier 7 effort last time it was available for missions.