Trade Union? Number probably how they registered the company. Jspoel 23:25, April 19, 2014 (UTC)
I know this is a few years late, but I think the answer is that it is a phone number. In the United States, through the 1950s or so, phone numbers were alphanumeric, using a two letter, five number system. In the mid-1950s, the system was standardized and numbers were assigned to the letters. "TU" equated to "88" which filled out the telephone number to 888-9130. I researched numbers in Nevada for real estate companies from that era without luck, even using area codes 702 and 725. Oh well :) -(Kdarrow (talk) 04:50, June 1, 2020 (UTC))
23:25, April 19, 2014 (UTC)