Approximate age of a George Wostenholm & Sons Original pipe razor

I just bought a George Wostenholm & Sons original pipe razor and was wanting to know the approximate age if it. I'm looking on the Uniclectica Staight razor manufacturers and dates of operations but am a little confused as to the dates they show. One of the date ranges says "Rockingham Works 1694 - 1847" and another date range says "Washington Works, Sheffield, Ca. 1847 - at least 1991. The left side of the blade says "Original Pipe Razor" in an arc form starting at the center forend of the blade, going upward to the center of the blade just below the spine and back down to the center of the blade toward the heel. Underneath that, in an arc going the opposite direction (toward the edge), it says "Medium Hollow Ground". In between them is a funny little curved line with a little triangle on the end closest the toe end of the blade. I was hoping someone may have some info on this. I'm a nostalgia nut, meaning, the older it is the more I like it. Thanks!

My straight history is not well-fleshed out by any means, so it is possible someone will have more insight later. From my understanding though the hollow grinding out is, while not limited, more of a later trend in razors. I suspect it is from the second forge works though as to the date inside that range I would have no basis for stating that I suspect it is from the early part of the 20th century.

Either way I have the same Wosty and it is one of my favorite blades.

Very approximate 1870 - 1890.