According to those articles by Mal Ferrell in NGSLG (Sept. 2011 through May 2012) both the 167 and 168 carried short smokeboxes and diamond stacks. They were classified as 45 1/2 class. They were later upgraded with extended smokeboxes and straight stacks and were reclassified with the other 4-6-0's of the series as 47 Class. All of the rest, including the 169, were delivered with long smokeboxes and tall, thin straight stacks. Over the years the cinder catching equipment became more efficient and smaller and the engines were modified with the shorter smokeboxes and shorter, fatter stacks we are used to seeing in the photos of T-12s in their waning years.
Bottom line, 169 didn't wear a diamond stack until fitted with a Phraudostack for the Worlds Fair.