Locking surface engagement in the M99

My 30-30 M99 doesn't seem to have a whole lot of engagement on these critical surfaces. The rifle hasn't seen a whole lot of use. Honestly I think the 90 rounds I've put through her are more than she's seen since '37.
Anyway. Her primers stand a bit proud, so I took an unfired case. Measured the rim thickness ( Remington) and got .059. Measured the case length ( 2.031) seated a primer and chambered it. Measured the length again and got 2.038. Took the difference, .007 and added it to rim thickness for an actual headspace of .066, which is .003 over minimum. Her chamber has just enough tool marks to prevent full setback on firing, but the actual headspace tells me I dont have an issue.
Back to the locking surfaces. I would like to see more contact. Viewed from the top of the action, there's little on the right, solid across the bottom ( about 1/16 depth) and pretty decent up the left side. I would rate total contact at about 30%.
With use, will these surfaces wear into more contact, or will the heat treatment of the receiver/ bolt prevent this? Do you think it would be worthwhile to VERY CAREFULLY lap the bolt/ receiver, sacrificing a couple thousandths of headspace, to better support the lock up?
Appreciate your thoughts on this.

What problem are you trying to solve?

The design calls for full engagement of these surfaces. Otherwise, the load is unevenly distributed, which can lead to cracked receivers/ bolts. Granted, the .30-30 doesn't stress an action very much. This would concern me Moe if she was a 300.

Ah, so, thank you.