YB calls it variation 12, with a rarity of 1 (least rare, and most of the 15 variations illustrated are a 1 or 2). The book makes no attempts to nail down a time period for any variation, and the variations don't necessarily appear to be chronological (var. 13 has only ERIE, not ERIE, PENN. or ERIE, PA). I would guess a variant of the EPU marking would place it somewhere 1920-1940.