I am new to java, working on it from the last three months
Honestly, in your case it would take pretty long time to grasp 1.4 concepts
and 1.5 as well. If you are thinking of getting into job market pretty soon ,as in 1-2 months, I will suggest SCJP 1.4.
However if you got quite a time to prepare, then you can work for SCJP 1.5.
Answer is
Depends
!
Other thing is that once you get 1.4 certified, you can easily take 1.5 upgrade exam ,providing you a good learning curve time as well.