Yes, I agree with your conclusion. RH for Roelof Helweg, registered in Amsterdam 1776-1811. Year letter Y for Amsterdam 1807.
The hatchet, the 1853 duty mark for old silver objects of national origin returned to the trade. In accordance with several resolutions with further clarifications, this mark was intended for objects with the hallmarks of the ancient Netherlands silversmiths companies.The use of this mark was abolished in 1927 for two reasons: 1st . The lack of knowledge of the old marks has caused this mark to be sometimes struck on old foreign objects. 2nd. this mark had often been counterfeited and used to give objects an antique aura.
For information about firm Helweg see: viewtopic.php?f=5&t=28590#p81398