Hi Tu Fan, from left to right; Fineness mark ٨٠٠ 800 or 80% pure silver, regional assay office Cairo, followed by the Nymphaea lotus flower blossom ( the lotus flower), the silver hallmark, and this lotus mark used 1946-2005, followed by the date letter for December 1997- October 1999.
Arabic letters have been used Since 1940/41. Starting in 1951, letters were used for a range of years rather than a single year. Inconsistent Arabic writing, some letters differ from one another only by an additional dot or loop, and because loops often appear closed,resembling dots, date marks can be very difficult to decipher. Letters were reused decades after they were first used. Image attached (can be saved from here and zoomed in). Either 1949 or 2002 (the dot).
It looks like your date letter chart differs with the date letter chart shown in World Hallmark Volume II or either I made mistake. At the moment no access to my books. Next week I will show you my copy of Egyptian date letter chard.
The date letter is for 1947 from Egyptian Year-Date Hallmarks-Phase II Arabic Date letter Conversions- 1940 to date, including Formal and Visual Arabic letter Comparison. Hallmark Research Institute with assistance from the Cairo Assay Office. July 1947, pronounce X, Arabic, Visual