No, that’s what I’m doing, though rather than having to enter the rails console and find a way to do a Permalink.create for every URL, I’m doing that automatically in the importer. Normal People should not be subjected to the Rails console. 
My current hypothesis is that it might actually be (a very tiny bit) better to have Discourse do the redirects than to get Nginx to do it, as adding that redirect will cause Nginx to have to process it on every url request.