Two X William III 3d's - Milled or Electrolysis?

[Coinery]

Hi, Again!

Any thoughts on the following? I have recently been given 2 William III threepences (1701 - 1698) in exchange for a favour, both in High-Grade. They are convincing in every detail (to me at least), having crisp detail (even haymarks on one), and beautiful toning to the 1701 coin (the other being unfortunately bright).

They both test positive for sterling, and the weights are right. I also cannot find any recorded 3d forgeries online, and cannot think of any reason for producing a high-grade, low value, contemporary coin in silver.

However, and here's the question, both coins are showing what looks like a partial seam around the edge for 2-3mm on one coin, and around 7-8mm on the other...the remaining edges are intact and showing no signs of filing, etc. Could this possibly be a 'seam' created by the 'spilling' over of the edge? Namely, the creation of an 'M' profile to a portin of the edge, with the middle part of the 'M' forming what could look like a seam (if you get what I mean)? Or are we looking at two fakes? Any ideas why they would have been be forged, if they are?

I attach an edge for you to look at.

Many thanks, once again,

Stuart