Hi,
Could be possible. Perhaps an import/export plugin might be able to do that. Although if you have a lot of products (thousands), I would highly discourage using custom fields – as it would be repetitive, taking up a lot from the post meta table. Using taxonomy terms (like categories) could be a better idea – as the same tags can be assigned to multiple posts.
Do you happen to know the names of these user meta fields? If these are all user meta, then using the index table engine there might be a way to use a custom code – to index these meta data along with product descriptions (sort of).