The overall evidence so far points to this being a Kai Ni is that.
1. Ichiso mentioned in his tweet that those that got the KC Calander got a nice "Surprise" he left in there as an "Easter Egg"
2. Tanaka's Recent Interview notes that a Shiratsuyu-class DD will be getting a remodel early this year hopefully around January.
3. A Dev tweet just a few days ago mentioned about a "DD that was part of the 4th Torpedo Squadron" (which Murasamae was a part of) that partook in transport operation will get a remodel soon.
So yeah all evidence points to this being an early teaser for something to come very soon.