I don't think the spoon is made by Holmström, neither father nor son. Holmström didn't make cutlery but jewelry and objects mostly in gold. However, I do think that this AH is Adam Herttuainen (read this link
viewtopic.php?f=46&t=43421&p=124418&hilit=herttuainen#p124418) irrespective the mark having similarities with Holmström's mark.
Adam Herttuainen had specialized in making cutlery, knifes, spoons, forks etc. He was also a subcontractor to Morozow.
About the engravings, yes it is a count's crown but the initials are SR (possibly RS) not a single R. As already mentioned by AG2012, it is more or less impossible the trace the owner. The only thing you can say is that he is not Russian because of the Latin letters.