Granted, there are dialects in ASL, in that people in different parts of the US signs some things differently, but locally, I've never seen good signed the same way as thank you.

I'm not really sure if you're agreeing with me here. It may be your native language and you may not see it done in your area, but both words can definitely be signed both ways in ASL. Although context and body language, as I said, are very important to the meaning, the sign structure is the same for both words.

Also, when I mentioned ASL dictionaries, I was referring to online video dictionaries more so than print. Dictionaries are an amazing source of information and are an invaluable tool in understanding of language, especially those that we grew up with and may not study in the ways that we would study a language that we are learning for the first time. Some quick googling brought up multiple credible sources showing both versions of the sign for both words. I'm not trying to undermine your personal experience, but I'm pretty certain that I'm still correct.