Odd. I don't think I've seen that on any other Boss -- regular or self opener. An it doesn't have anything to do with the self-opening mechanism. The Boss system works off of a V-spring mounted under the cocking rod.
Those pins look pretty messed up and the insets are shoddy. Doesn't look like Boss-level work.
All the Boss self-openers I've seen (maybe a dozen or so) had has those screws in the forend. They're locking in inserts which are filleted into the forend iron to take up wear that's a by product of the self-opening system.
I've also seen those screws/inserts on a few non-self openers. I think they were '50s guns.
Here are some true Boss self openers for reference:
Little ratty, but real:
https://stevebarnettfineguns.com/boss-shotguns-for-sale/best-sxs-16-gaugeThis one's awesome. One of the very best:
OWD