I’m guessing that you’re asking about OpenGraph and Twitter meta tags for each individual post. If that is the case, then yes, each post receives both sets of tags, and you can customize it with your own account details in the main Alloy Control Center stack. This allows for the social media “cards” you often see when linking to OpenGraph and Twitter meta tagged pages on platforms like Twitter, Facebook and the like.
It is going to be a copy and paste operation. If your current service has the ability to export each blog post to its own Markdown file that might speed things up a bit. You could then just add in the necessary YAML Front Matter for each post and then upload them to your posts folder using FTP. But most likely you’re probably going to be simply copying and pasting content.