I made a blog about this over a month ago but I did not get as many responses to the confliction of the abilities of Gold Kryptonite.
There is conflictions between the effects of Gold Kryptonite on Earth and in the alternate Earth-2. On Earth-2 Clark Luthor claimed that Lex used Gold Kryptonite to scar him on his arm with the letter "L". If this is true he would have lost his powers permanently and would not have been able to use them in the episodes "Luthor" and "Kent". Is it possible the effect differs between worlds or that Clark Luthor had his powers returned some how? Whats your opinion?
We need to update the page Gold Kryptonite to the information given in Kent, Prophecy and Finale.