After receipt green card

[kann]

Hi,
My parents were in US and applied for GC.
Interview was in DEc 2009 and they left for India
immediately after the interview.
They have travel doc valid upto Aug 2010.
10days after the departure to India,
their Green Cards were recd by me in US.

Can they come to US now with the travel
documents or they have to show their
green cards at the immigration counter upon
arrival.
In that case i have to courier the Green cards to
my parents in India.
Is that OK?
PLease help/ advise what we need to know,

thanks.:

[cpulb]

To be on the safe side, just send them their GC by mail.
But they should be able to come back in without problems since they had their I-131 approved.