Sorry to be the bearer of bad news, but CA Registration Numbers on clothing labels are likely of no help for researching dates of garments.
I decided to see if the CA registration number could be useful, so I went online to look up ‘CA01937’ – the number that appeared on the label of a blouse from c. 1980 with the manufacturer’s brand name “Crossroads from Montreal.” The online search resulted in Dae Woo International Co. – currently a manufacturer of automobile textiles. According to the site, the number was issued on September 25, 1997 but I knew the blouse was older, not only stylistically, but I had a photo of the original owner wearing it in 1981.
I contacted the Competition Bureau in Ottawa and received a helpful reply from Mr. Yves Chartrand who explained that Canadian manufacturers, processors or finishers of textile fibre products, or Canadian businesses engaged in the importing or selling of textile fibre products can register for a CA Identification Number. He verified that CA01937 belonged to Dae Woo International Co., and was originally issued on March 7th, 1973. However, when the Competition Bureau upgraded the database to an electronic format in 1997, the limitations of the program could only register the original date of issuance as the date the data was put into the system, hence all issuing dates in the database are 1997 or newer.
The holders of CA Identification Numbers are responsible for the accuracy of the information in the database and for advising the Competition Bureau of any changes. Dae Woo had not submitted any updates since the original issuing date, so the 1997 date remained until Dae Woo informed the Competition Bureau of the change.