From the audit there was a low priority issue related to

Missing early timestamp validation in RollkitEngineValidator method

This was done on purpose for rollkit specific validations.

If this wants to be supported we need a way of using a custom header. We can get inspired by something like github.com/tempoxyz/tempo/blob/f9f539a66815625961d38feb99b86dca2609e2f2/crates/primitives/src/header.rs#L30