One of the easiest way to determine pressing plants for RCA Victor’s later 78s and early 45s and LPs is from subtle clues in the label design. Victor revealed them in the Standardizing Notices pictured below in 1947 (for 78s) and 1950 (for 45s). For 78s, the clues lie in the concentric rings, and their spacing relative to the circled RCA logo; for 45s, in the placement of a double hyphen within the upper text circle.
“Canonsburg” refers to RCA’s auxiliary plant in Canonsburg, Pennsylvania, which opened in 1947. In 1950 it was converted to a 45-only plant, then was closed in 1953.
Indianapolis text above, which is unclear on the original, reads: “Two concentric circles nearly touch small RCA circle.