Let the hive mind of Engadget get that for you.
"I'm in the market for a new phone and money isn't a limitation. I'm also not partial to any particular US carrier, but here are some of the features I'd like to have: WiFi, GPS, good coverage in lots of places, push Gmail (a must!), physical keyboard (a must!), a touchscreen, decent battery life and a relatively slim body. And please, nothing that has a fruit logo on it. No offense to the fruit fans, though. Thanks!"
If this is 1.3mm, then current gen LCDs are about 1.9mm (1.9 - 32% = 1.3). That means you can't expect Samsung to reduce the SGH-X20 to less than 6.3mm from the display alone, not 4.83mm.
Looks like someone didn't do very well at junior high math.