"ish".
There's a series of config files (in /home/hts/.hts/tvheadend on a 'buntu installation) that you can back up, making sure that you keep the file permissions in the process.
You'd need to ensure that the default tvheadend user is the same after the upgrade (hts by default, so it should be) and that all the adapters initialise in the same order. That last bit might not be so easy, depending on how they're connected (USB moves all over the place if you're not careful) and how the new OS handles them compared to the old.
You'd have to give it a try and be prepared to rebuild it if necessary. That said, it's not a big job to trash the whole config and let it repair itself and re-scan; it's only hard work if you've done a lot of customisation of logos, channel merging, etc.
