The last date I can find on my plate is when it was last patented which was August 2nd 1892...no other dates are there..I actually checked the Smithsonian website the day I got her but haven't really delved into it yet..it didn't seem to have the D-9 that I saw...Mine is the regular 3 drawer cabinet not with the coffin top lid...
I have been using Goop to clean it up..it had lot of grime on it...I replaced the belt on my 1912 White treadle and it sews really well except i go backwards more than forward..there are alot of things on the web for replacing belts...I bought mine on ebay.