It's been many years since I owned whole life insurance, but my recollection is the dividends were considered return of premium and not taxed. In my case the dividends were less than the annual premium and were applied to reduce the amount I had to pay each year so I never saw any cash. I cashed those policies in long before demutualization.

I now hold 42 shares in MetLife as a result of demutualization. These are shares I inherited from my mother, who had a couple small policies. I do get a dividend check each year and the accompanying statement also serves as their 1099. Through 2012 they paid a single dividend in December. Beginning in 2013 they are going to pay quarterly so I don't know what their 1099 policy will be. I do know they are going to waste a lot of shareholder money sending very small checks out. Many small shareholders like me left their shares in trust with the company, which is why they send individual checks. Maybe they'll offer to transfer the shares to my broker without fee. That would be acceptable to me.