It's not keyed cuz it's really not a [harmonic] balancer. It's just a crank pulley. It does have rubber isolation between the outer ring that the belt rides on and the inner hub to dampen asynchronous vibrations.
The crank pulley bolt is torque-to-yield (TTY) so it must be replaced. Yes- it's a perfect time to replace the front crank seal and front cover gasket. Be aware that the cover must be in proper alignment so that the seal is perfectly centered around the crankshaft, otherwise it'll wear more on one side and leak prematurely. There are alignment tools for this.
Also, while the VVT system is generally reliable, the cam phaser is known to act up with age. If I were that close to it, I'd replace it as well.
Oh, back the the crank bolt- if you don't wanna deal with the TTY stuff, you can get an ARP bolt and just torque it as they specify. I've always used the stock TTY bolt. I use a protractor to put "0" and "140° marks on the pulley, install it and torque the bolt, mark the bolt at my "0" point, then rotate the bolt until the mark on it aligns with the "140°" mark. Pics and description >
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