Steddick,
The official model number listed on the television's model and serial tag is LN40A500T1F/[country code]. I've seen some threads on the internet that pose the same question.
One retailer may put emphasis on the "T" to seem different (extra characters often suggest an additional feature) or do it unknowingly, but that does not speak to any change. In the case of owning an LN46A650, the sticker behind the right hand side of the panel with the serial number will also indicate some additional letters and numbers. I still refer to it as the LN46A650 even though it is technically the LN46A650XYZ/XXA. If someone wanted to advertise it as such, we can't stop them, but it doesn't change the internal parts of the unit, despite speculation.
Translated, If someone said they have the LN46A650B or the LN46A650B2F or the LN46A650B2F/XXA or any additional alpha/numeric combination thereof, I know without a doubt that we are discussing the LN46A650.
I hope that clears this up. Let me know if you have any further questions.
--HDTech
What is the difference in the above model numbers? Is there truely a difference in parts used or not? Anyone..... Thanks

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic