18th century?

Among a bunch of old wooden planes I spotted the tell tale signs of 18th century Dutch moulding planes. The typical decorative gouge and chisel cuts on the front of the planes are quite short on the old ones and a lot longer on the 19th century planes. These planes are otherwise also old fashioned. The cutout in front of the blade on top of the plane is very deep and well defined. The later ones are usually quite mellow. The planes are made from beech which is exactly radial, also a sign of the better quality back in the days. And last but not least, the irons are thin, only 3mm near the cutting edge. Later ones are 4 to 4.5 mm thick.

But, I can't be sure because there is no makers mark. The only mark is PDO, which looks more like an owners mark to me. The mark doesn't look very old either.

If someone knows more about PDO, feel free to add a comment.