Perm approved but left the company

[pashah]

Hi,

 

I was working for company X and they started my labor in Mar '15. I joined company Y in Aug '15. Last week I got email that my labor got approved. 

 

My company Y will start my GC process soon however they yet to start with the posting the advertisement. 

 

1) Should I Ask company X to file for I-140 (I am ready to bear the expense). What benefit will I get?

 

2) If yes, Can I use that approved I140 to port the date? 

 

Thank you