If you export via TOOLS -> EXPORT -> CONTACT FORMS and then import them via IMPORT -> FROM WORDPRESS, then there shouldn’t be any issues.
However, since ID’s can change between exporting/importing, we’ve always found it easier to copy an entire DB to the new site and just modifying the URL’s via DB Replace tool (see https://interconnectit.com/products/search-and-replace-for-wordpress-databases/ )… this way, ID’s are maintained and nothing breaks.. but this isn’t recommended for existing sites as you’ll lose everything (unless, of course, the dev site is up-to-date already).
If anything, after doing the export/import, you may just have to go back through your pages and reassign your CF7 forms.
