Good thinking. You're right, there are different parts for the FE and FEH:

Escape: 5L8Z-7845440-AAB
Escape Hybrid: 5M6Z-7845440-AAA

I suspect the battery vent on the driver's side in the rear FEH requires a different size rod and that the salesman ordered the wrong part, or just picked up one they had lying around not realizing what it was.

Robert