According to G. Byrne Bracken in his book 'A Walking Tour: Singapore', there are five different shophouse styles in Singapore that were constructed between 1840 and 1960. The styles he mentioned are:
1. Early Style Shophouse
2. First Transitional Style Shophouse, Early 1900s
3. Late Style Shophouse
4. Second Transitional Style Shophouse, Late 1930s
5. Art Deco Style Shophouse, 1930-1960
I believe from the design of the windows that these row of shophouses would come under the 3rd style i.e. Late Style Shophouse.