Thanks for your help, @Jason!
Yes, after more research, I agree that it’s Navajo; prior to my posting this, I was presuming Zuni (based on their history of using inlay) but the hallmark style points more towards Navajo. Also, it fits the timeline better. 
Would it be safe to consider that the material is Silver, as opposed to Sterling Silver?
The weight of the cuff is just under 22 g (exact wt. 21.93 g)
Cannot locate my metric caliper, but has a decent thickness to the cuff:
This hallmark is such a hitch for me.
If the designer was an ‘Allen’, I’m curious about their reason for use of lower case ‘L’s. Lost that L stamp?
OR
Aiien?
Regardless, this is a family heirloom piece that I’m preparing to pass along, just trying to get any info to include with piece.
Thanks again for your help!