Interesting also Brian. The gun dates to the early 20s, prior to Hunter Arms lengthening 20g chambers from 2 1/2", and the 2 3/4" mark suggests it may have been ordered as a small gauge waterfowl gun.
Does the mark look like this?



A research letter should provide significant information, and possibly who placed the original order
https://lcsca.clubexpress.com/content.aspx?page_id=22&club_id=43784&module_id=245742