Ulster's musical history - The Anglo American Gramophone Co, Belfast

This is a detail from an old 78 record sleeve loaned to me recently by a friend from Bangor called Jim Mayne. Maybe someone out there can guesstimate the date from the four digit phone number? Belfast was one of the first 13 local authorities in the UK to be permitted to install its own local telephone system in 1899. I expect that this might well have been one of the shops who sold old hillbilly and American gospel 78s to my granda and his generation. Nowadays the address is occupied by the consultancy firm ASM Horwath, who I've done some work with in the past.