I am new to this forum and found a lots of useful information for my newly bought pieces of old silver cutleres from Budapest. But here are some marks need help. They are all from one spoon as below imags showing. I could only recognize a Hungarian (be more specific, Buda) hallmark for year 1818, 13 loth (a three castle on top of 13). Above the Hungarian (Buda) hallmark there is a mark "N", on the right side of the hallmark there is "I G" inside a shield which I don't knwo what exactly it means. On the right-down there supposes a silversmith mark "R B", and then on the left-down there is something inside pentagon sharp which I almost certian it's not a Diana head.
Any help appreciated!
![Image](https://i.imgur.com/jiSwNll.jpg)
![Image](https://i.imgur.com/O93l4Tf.jpg)
![Image](https://i.imgur.com/9q9NmUu.jpg)
![Image](https://i.imgur.com/ThAcEYY.jpg)