was curious to see what your piano might look like, and my research leads me to ask, is your description of the instrument based on your personal examination, playing, measuring, verification of serial number and date of manufacture ? this is not a query expressing personal doubt, but from a lack of information about their grand pianos that small made at that time. their factory was like many others destroyed by allied bombers, and their production just beginning to restart in '52, which could explain the unusual size. the smallest grand they make now is about 12 cm longer, and there were 160 cm.(about 5'3") instruments in the 1920s, when the company like many other piano makers was in a boom period. by law, retail sellers in this country have to sell them under the name 'grotrian', omitting 'steinweg', because 'steinway' is actually the same family name originally and they succeeded in keeping their old world cousins' name off the (new) pianos sold here. your piano would have an interesting history, from the limited production in '52 combined with 'steinweg' on the piano.