Question about a Gillette Old Type

I have Gillette Old Type that I assume dates from somewhere between 1905 and 1920. I have read that razor blades were thicker back then, and for today’s thinner razors, the Old Type head has to be have a shim. My Old Type is one of my favourite razors, and I have never had a problem using Wilkinson Sword blades it it. Has anybody had to use a shim with this razor?

I enjoy shims in some razors, not so much in others. Have you noticed a difference in your shaves, shimmed vs. not shimmed?

I’ve never shimmed a razor. I don’t see any reason to shim this one. I just wondered why this Old Type works fine with modern razors and others don’t.