Google product search attribute requirements changing.

I just received an email from Google stating, "Starting May 3rd, 2011, we’ll require your product listings to include at least two of the three unique identifiers (Brand, MPN, GTIN)." MPN can be the manufacturer's sku, but are there plans to include at least one more of the aforementioned identifiers?

99% of my business traffic is through Google products, if there is something I'm missing in v1.9 that already includes this, I'd appreciated that being pointed out.

If your products already have GTIN, you can add it to your product RSS feeds by some customization. I think that's all you need to do .