First Duke of Portland's Tablespoon

While researching another piece of silver, I found James Garrard's 1893 catalogue of the Duke of Portland's plate.  The catalogue contains descriptions of each piece of silver in the Duke's collection, together with a section of plates depicting the arms, crests, and other engravings found on the silver.  While looking through the plates, I had one of those "aha" moments where it struck me that I had a spoon engraved with a set of the arms shown.  Below are the arms on my spoon.

The spoon was made in 1721, but the maker's mark is rubbed.  A scratch weight of 2=11 is engraved on the spoon heel.  I had assumed incorrectly that the arms were those of the Most Royal Noble of the Garter.  Looking through the catalogue, in the section Antique Spoons and Forks, I saw entry number 551 for "Table Spoons. Three rat-tail, Old English pattern.  Plate XXII, No. 5.  A.D. 1721. Weight, 6.5 oz."  Plate XXII, No. 5 depicts the same arms that appear above on my spoon.  Given that the date and arms match, is it too much to conclude that my spoon is one of the trio listed in this catalogue?

Even if it's not, it seems fairly clear that this spoon did belong to the Duke of Portland, and specifically to Henry Bentinck, the first Duke.  After having been a Member of Parliament, Henry was appointed captain and colonel of the First Troop of Horse Guards on July 21, 1710.  By letters patent on July 6, 1716, Henry was created Duke of Portland and Marquis of Tichfield (Henry had received his wife Lady Elizabeth Noel's share of the Tichfield estate upon their marriage in 1704), and was in 1717 created one of the Lords of the Bedchamber.  Despite having inherited prosperous estates, Henry lost a lot of money in the South Sea Bubble in 1720.  On September 9, 1721, he was appointed captain general and governor of Jamaica, and he arrived in Spanish Town on December 22, 1722, just after a hurricane had devastated the island.  He died in Jamaica at age 45 of a fever on July 4, 1726.

It would appear that Henry had these spoons (and presumably other plate) made to take with him when he was appointed Governor of Jamaica.  What I am not certain of is if Henry received a plate allocation from the Jewel House, or if he paid for the silver himself.  The scratch weight leads me to believe it was government-issued, but the scratch weight could also have been applied during a later inventory.

Sources:

Calendar of State Papers Colonial, America and West Indies: Volume 33, 1722-1723. Ed. Cecil Headlam. London: His Majesty's Stationery Office, 1934. British History Online. Web. 13 April 2020.

 
Collins, Arthur. Peerage of England; Genealogical, Biographical, and Historical. Vol. II. F.C. and J. Rivington, 1812. Google Books. Web. 13 April 2020.

The English Encyclopaedia: Being a Collection of Treatises, and a Dictionary of Terms, Illustrative of the Arts and Sciences. Vol. V. G. Kearsley, 1802. Google Books. Web. 13 April 2020.