Currently Safari and Orion are indentical in terms of element inspector functionality. Namely the ruler can be toggled off in both via the ruler button:
Regardless of toggling the setting mentioned above, the ruler appears when hovering over a line in the HTML code. This is the case on both Orion and Safari, and the functionality makes sense to me. I'd suggest marking this as done, unless the ruler appearing on hover is something that should be added to Orion. @Vlad
