I don't know if you really meant the title of your post to be a question. The answer is yes, it is completely fine to use an Evaliation License with an external database. This is not a limitation of our evaluation licenses.
It looks like the gents above were able to direct you on how to retreive your currently installed license. Please let us know if you need anything else.
Just adding to Jobin's response: you can indeed see which license you're using under Confluence Admin > License Details. Now, if you want to switch your current license to one of the others you have, you can simply login to https://my.atlassian.com with your credentials and you will see all available license keys.
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