@Holiday has PIFed this razor to me. I have started to study it in detail before attempting any restoration work. Here are my observations so far:
1. The razor is most probably French made as the name Bourdais is very much French. The blade's point is of the common French style and the stub-tail arrangement was most popular in France.
2. The scales are not of timber. They are of horn, including a horn wedge.
3. The scales' pins appear to be of a bronze alloy rather than the more common brass alloy.
4. The blade is of a near-wedge grind. The grind is not symmetrical (but close to it). This would indicate that it was done on a single grind-stone wheel rather than a matching pair of wheels that didn't come into use until the mid 1800s.
5. The razor was probably an original ⅝ size. Over its years of use, the blade is now worn down to almost a 4/8 (13.7mm) at the heel and 15mm towards the toe.
6. There is some pitting on the bevel (face side) but hopefully this does not extend so deep into the steel that it could affect the edge quality.
7. For age, I would estimate that is was made late 1700s to early 1800s.
Over the coming weekend, I will look into starting some basic restoration on this SR. Once all is done, I will offer it as a PIF. If no takers, I will keep it for personal use as my oldest razor.