I have one of those one piece Gillette razors; it's stainless steel and has a graduated tension setting to adjust the blade. I bought it sometime in the 1960's; it's in our what-not cabinet, along with one of the old brass two piece Gillette razors that dates from the 1940's.
I came across two of those old brass Gillette razors at a yard sale a few years ago,, one was still in the box. Then a few weeks later I found a box full of the Government Issue blades, 100 count.
They make a nice addition to the straight razors that belonged to my grandfathers.