It does appear that way with the picture on the front of http://www.sun.com clearly showing the text "Sun Cobalt" on the upper left and LX50 bottom right.
Yep, it's kind of odd actually. All the Linux stuff is coming through the Cobalt group, so I think the "Sun Cobalt" logo is there because it's Linux-based (although I don't believe there's a separate bezel for the Solaris-x86 folks) but the "official name" for the server is just "Sun(tm) LX50"...
Regardless, when you all place your orders, you can call it anything you like and we'll be happy to ship them off to you! :)
-- Bruce Timberlake Cobalt/Linux Technology Engineer Communications Market Area Sun Microsystems, Inc. - San Diego e: bruce.timberlake@xxxxxxx t: 877-718-3569 / x69369