Here is an excerpt of the SLA; the Lion license (purchased from MAS) is NOT transferable. The SLA is quite clear:
B. If you obtained your license to the Apple Software from the Mac App Store or on Apple-branded physical media, it is not transferable. If you sell your Apple-branded hardware to athird party, you must remove the Apple Software from the Apple-branded hardware beforedoing so, and you may restore your system to the version of the Apple operating systemsoftware that originally came with your Apple hardware (the “Original Apple OS”) andpermanently transfer the Original Apple OS together with your Apple hardware, provided that:(i) the transfer must include all of the Original Apple OS, including all its component parts,printed materials and its license; (ii) you do not retain any copies of the Original Apple OS, fullor partial, including copies stored on a computer or other storage device; and (iii) the partyreceiving the Original Apple OS reads and agrees to accept the terms and conditions of theOriginal Apple OS license.