Is it safe to swap the "duckhead" connector from an old power supply to a new MagSafe 2? Working from home today and I just pulled my macbook pro out to realize that I left the "duckhead" part of my magsafe 2 power supply (85W) sitting on my desk when I left the office last night. I happen to have an old power supply from (I think) a PowerBook G4 (65W adapter) that has a similar design with a detachable "duckhead" piece. But I can see that the two power supplies are definitely not identical.

Is it safe to swap the "duckhead" from the old power supply onto the new magsafe 2, or do I need to head in to the office? The "duckhead" from the old supply seems to fit on the magsafe 2 adapter just fine, I just don't know if it is safe.
The duckhead is very simple and it's safe to swap.

When you buy Apple World Travel Adapter Kit, you get various connectors that work with their whole range of AC Adapters.  There are not different models.

http://www.apple.com/shop/product/MD837AM/A/apple-world-travel-adapter-kit