Using the standard tests (with `CUSTOM_METADATA_MANAGER_DEBUG` set to `true`) the existing code clones the number field with value intact:

![screen shot 2014-03-20 at 12 13 35 pm](https://f.cloud.github.com/assets/605361/2474361/ae842478-b04a-11e3-8653-c064188f73fc.png)