Mounting a camera on the lid is pretty good, but it is not reliably within mm upon opening and closing it. It will certainly work well for things like material usage / placement, but I would not rely on a lid mounted camera for indexing a job to engrave a maker’s Mark on a one-of-a-kind wooden sculpture. 
If you have alternatives to consider for mounting locations, you could try those. But also think about how alignment could be affected. For example, a ceiling mounted camera is at risk of the machine moving.
I know a guy who made a crazy mount for his lightburn camera: