1) IF you have a PAL
2) IF you have an ITAR export permit from the US
3) IF you can convince the customs officer that the receiver is real steel
4) IF you have it stamped with readily identifiable registration numbers
5) IF you register those stamped numbers and the receiver as a firearm as it enters the country....
... then yes. You could get it across legally. But if the officer finds out that it's for airsoft, they could charge you for attempting to fraud customs, which could potentially land you with criminal charges.
Is all of that work, trouble, and risk worth it to save $100-$200?