Two Arkansas banks have added to their inventory of brick-and-mortar locations during the first quarter and two more have new branches in the works.First Security Bank of Searcy expanded its Arkansas-only network to Russellville. The full-service branch is No. 74 for the $5.2 billion-asset lender and its first in Pope County.Piggott State Bank opened its first branch outside of its hometown in an intracounty move. The Rector office, 13 miles away, is the $80.9 million-asset lender's second full-service branch.Diamond Bank of Murfreesboro is going to Texas in its latest move. The Texarkana branch would transform the $528.7 million-asset lender into an interstate bank.Cornerstone Bank of Eureka Springs intends to open a full-service branch in neighboring Boone County. The Harrison location represents the sixth location for the $215.4 million lender.