Could you help me identify these vintage bricks with holes in the studs? I recently got a bulk lot of official Lego pieces from a charity shop. Amongst my treasures I discovered a load of these bricks (about 40 or so).

At first I thought they were some of the first Lego bricks but as far as I can tell Lego have always had the tubes on the underside of their bricks. Can anyone help me to identify their pedigree and/or their age? I have a very strong feeling they're knock-offs...

Distinguishing features - 


These bricks have nothing on the underside to stop them from sliding around- no tubes, ridges, nothing.
The larger bricks (2x4 upwards) have holes all the way through the studs.
All bricks have a slightly sunken profile to the studs
Every brick has a random number on the underside i.e. “43”, “78” etc
In basic colours of red, blue, yellow, white, black and clear. I’ve also got a green baseplate which has square holes on the underside.


Thanks for any help you can give me.
LEGO made plastic bricks from 1949 and didn't get the patent for the tubes underneath until 1958, in the years between they made plenty of bricks with nothing underneath.

Many (I don't remember if it's all) of the (larger) LEGO bricks from that era, has a slot in one side.

That being said, with the small holes through the studs on the 2x4 and the slightly recessed studs, these bricks doesn't look like anything I've ever seen from LEGO.

Square holes underneath I have seen though, so that's not an argument against your green plate being LEGO, but without having seen it, I can't say for sure.