Hey Capn Mark!
I knew I could count on you to answer! We always have the same curiosities
Actually from what I have found so far, these dates range from 1730s into 1770s. I recall some years ago when it seems I had come across a number which had 1768. In discussion back about 2011 someone had one with 1606 and the VOC and you brought up a 1660 similar if I recall, and I believe that suggestion regarding talismanic numbers was more in place than these 18th century examples.
I had thoughts these might be issue dates, similar to the 'dump' coins for trade, but then found that regularly hilted cutlasses had these dates and balemarks, so they must have been issued to VOC sailors whether as individuals or rack, unclear on that.
As you note, Jasper will likely have good insight here and hopefully he will see this.
All the best,
Jim