It seems to me that if the bolt is free and it doesn't cost much to check headspace, then why not?
And if it doesn't help, then I guess there's two ways to look at this. One, you like the rifle, it has worked for you, and shot well enough for the hunting you use it for. That being the case, just confine your paper punching to checking zero and quit worrying about it. At the risk of having my gun loony card revoked I have rifles in that category. I have others to use when I really want the higher precision too.
Otherwise, having more or less tried everything, if you really couldn't be happy with it, you'd send it down the road, or over a gully bank.
