PART ID from photo?

[jjrothWA]

Part OAL with DIMS 27OCT2020.jpg


Does anyone recognize this part, as for being either a Ithaca / SKB Model 900, Brwng A-5 lightweight 12ga?

Thanks.

[Sunray]

Any part of it threaded?
Not seeing anything remotely like it on GunParts Schematics or either model. Which aren't enlargeable enough for this geezer to see it well.
Not seeing it on Auto 5 exploded drawings I can see either. Lots of free .pdf's on line.
Or on SKB drawings.

https://www.skbshotguns.com/owner-support/guides-manuals/parts-breakdowns