1900 upfranked Charity advertising letter sheet, Reval/Tallinn railway station-Babruysk-Mogilev (Belarus)

Very scarce upfranked advertising letter sheet number 39, issued 1899 in St. Petersbourg (Michel F3).  Only 5000 issued. Posted June 14, 1900 from Reval railway station (postmark H/O 3:6) to Mogilev, Belarus. Transit postmark Babruysk 16.06.1900 and arrival postmark of Mogilev 17.06.1900. The letter is upfranked with addional 7 kop of stamps and bears inscription “Заказное” (“Registered”) on front, which means the sender meant to sent to registered (rate 14 kop). However, there is no R-markings on the letter.  It is possible that the letter was left in collection box and “Registered” marking was left unnoticed by postal clerks, as 14 kop was also rate of second weight class non-registered letter.