1776 Guinea Half Weight? George III?

One of these was included in a miscellaneous lot sold by Spink

https://www.spink.com/lot/341000341

Although I can find little else regarding it. Interesting find.

To add a bit, this can be dated to 1772-1816, so the 1776 date is likely correct (and as pointed out Spinks did have one in a lot.)

The D G / 2 16 should be read as 2 dwt (pennyweight) and 16 gns (grains) (2 dwt is appx. 3.11 grams and 16 gns is appx. 1.04 grams, so 2dwt 16gns = appx. 4.15 grams)

20 dwt = 1 oz t (Troy ounce.) 12 oz t = 1 lb t (Troy pound.)

The ewer countermark is historically a mark of the Worshipful Company of Founders, but since this dates after the early 18th c. it is much more likely to be "in the style of."

If you find this sort of thing to be interesting, the British Numismatic Journal had an excellent article by Mr Norman Biggs (2001, vol. 71, issue 11, pp. 111-117, q.v.) that goes into more detail of the Founders and Blacksmith Companies and provides a general historical overview of bullion and coin weights from ca. 1550-1800.