I found this photo of a similar front sight on a current Gunbroker listing:
It looks like mine lost the white insert, and the steel ball was substituted.
I'm not sure if its OK to post a link to a current auction, so I won't. If you search "Ruger .44 carbine original peep and swivels" you'll see it.
So, could this be an original sight? I've seen references to early .44 carbines that came with peep receiver sights, could this be the front sight used on those guns?
The carbine in this old Ruger ad looks like it has this type of sight. 7 ‘Old School’ Deer Rifles That Can Still Bring Home the Venison