You win the lottery. From what I could find AMLCD 220M1 does refer to the newer S panels (the [R] is unimportant.
http://www.behardware.com/articles/667-1/samsung-226bw-a-and-s-series-the-verdict.html
I believe the R you are seeing is normal and not an indicator of a model or variant. In some pictures I've seen that people have posted on-line in regards to the BW lottery the [R] always followed the model and came before the variant, i.e 226BW [R] S (or A or C)...
You can return it to your local store if you order it online from Best Buy online. I might have to do the same because the product page says it may not be in all stores. Though I'm waiting to see if it goes on sale on Sunday by any miracle.
Sometimes the search on Bestbuy is screwed. Not to mention on the product page they say "From our expanded online assortment; not available in all Best Buy stores". What the heck is that?
http://www.bestbuy.com/site/olspage.jsp?skuId=8400456&st=226cw&type=product&id=1179877503230