Providing for a sling-Roger Lewis 1756 gun

[bob in the woods]

In going through the book, " Of Sorts For Provincials" by Jim Mullins, I'm intrigued by the American Fowler marked
Roger Lewis 1756.  I love the gun's overall architecture , however I wonder about the provision for a sling seen on the forearm located at the entry thimble.  Looks like an enlarged , forged staple.  Has anyone seen this type before, and has anyone actually tried it ?
Thanks

[bob in the woods]

This "staple" is not something I've seen on any other gun. It's location seems odd as well, [ entry pipe ] since the barrel on this gun is 52 inches long .   It's a really nice gun, supposedly used during both the F& I war as well as the Revolutionary war.   
Contemporary Builders site has a reproduction posted, built by Ken Gahagan . It's superb, but the "staple" is missing from his rendition, although there are holes located in the appropriate location.

[Stophel]

I'm sure it was intended for use with a carbine sling... though it's a mighty long gun for a carbine sling.

[conquerordie]

There were someNew England Calvary in the field , or at least groups of men on horseback  fighting in 1776-1778. So a carbine sling, on horseback with a long barrel could work. We will probably never know for sure.