Have you tried the Webform share module (it is a helper module to prepopulate newly created webforms and to export / import webforms between sites), it may be helpful for this scenario as it provides the following feature:
Example usage 1: Prepopulated webforms
Create a webform with the required components.
Export the webform
Edit the webform content type and paste in the content from the export (under Publishing options)
Use the standard node add content links and each new content item created should be prepopulated with the exported webform.
Example usage 2: Synchronization of webforms
Export the webform that has the settings you want
Import these over the existing webform.
Note: Existing webform components are replaced with the new webform components. If a component is dropped or the key is renamed, you will no longer have access to any user submitted data.