Markings on the reverse of the spoon bowl????

Hello,

Iv’e come across several old tea spoons with markings on the reverse of the bowl which I’ve not seen before, can anyone tell me if this is rare to find? Thank you

Picture-back spoons are not that common and 18th century examples are sought after. Late 19th century and 20th century examples can also be seen. Typical pictures include flowers, foliage and ships.