Jeff, You are probably right.
I'm pretty sure too that they are all build at the same place, probably China and are distributed all over the world but each seller with put their own model number on it.
Here at home, I have several switching power supply and some can be connected parallel and some not, all depend on their basic design.
Just look at stepper driver you can buy from China, They are the same as those we can buy in North America but with different model number.
Some are cheaper, but often, they are identical.
Mr Birt, By the way, nice website