Historical telephone numbers

Today I was reviewing a notebook of my father's dated 1962 whose cover is marked with the intriguing LON 2178. At the time he would have been living in Manchester, England. Surmising that this code may be a telephone number, I discovered from Roger Haworth's website that in the Manchester Director Area the LON (dialed as 506) would have connected to the Longford exchange. As the present-day Longford exchange is little more than a mile from a street on which my parents lived long ago I surmise that the marking on the notebook is indeed most likely to have been their telephone number back then. The Internet and its denizens make it agreeably easy to research such matters.