Yeah I too opened the Wearable app and was told of an update last night. So I did the update. Just noticed in the Playstore that I've got a WiFi update from Google also. It's a system app by the looks, so I will update.
To be fair I don't blame you for being a bit paranoid. I don't use auto update for apps. I'll give them a bit of scrutiny before updating manually. I always like to read the change log to see what they've adjusted first 👍🏻