Cant help with your research Beanhead. But I was researching the company a couple of weeks ago when I bought a Tre Spade rip-off coffee mill.
The company was founded in 1894, so your anectode may well be right.
My own original Tre Spade is very sturdily made, with tempered steel conical burrs. But there is some wear in the crank shaft where it exits through the top cover.
My right arm has biceps of steel thanks to that little monster.
I had no high hopes for the rip-off, identical in shape, look and design. And, since I was the only misguided bidder on the Bay of Evil, $0.99 plus postage. Yes, ninety-nine cents.
When it arrived, my suspicions were confirmed. Some sort of cheap brass or aluminium in parts where steel should be. Too much wobble in the crankshaft. Extremely fiddly to adjust the grind due to poor workmanship.
But it is destined for the boat where it hopefully might make the odd plunger coffee to have with milk and toast for breakfast.