I don't know if you can really find a retro dim sum place in Singapore rather than Hong Kong but you can try out this place.
http://ieatishootipost.sg/2011/10/re...lleys-and.html
Red Star Restaurant
Blk 54 Chin Swee Road
#07-23
Singapore 160054
Tel: 6532 5266 / 6532 5103
Daily: 7.00am - 3.00pm / 6.00pm - 10.30pm