You know I'm not sure what year they did the change over but the old refg. was R-12 very, very expensive, the new refg. is R134. The conversion kits are less than $100, I did mine and I got it at Wal-Mart, easy as pie!
Do the change over, but, that's my opinion!
Good Luck! <img src="/forums/images/graemlins/kewl.gif" alt="" />