This one was minted for the 400th Anniversary of the Ducat: Netherlands Ducat 1986 Gold, 21 mm, 3.47 gm
Speaking of the provincial Utrecht ducats, you are right from 1586, till 1805 to be precise. Later ducats (Batavian Republic, Kingdom of Holland, The Netherlands from 1814) were indeed also struck in Utrecht but it's a different story What's interesting, although minting double ducats was introduced in the mint ordinance from 1606, the first double ducats were minted in Utrecht much later, in 1652 Congratulations messydesk on your new acquisition! That's uncommon date for Utrecht.