Very Old Skateboard (60s?)

A bloke at work found this old skateboard during Brisbane's last kerbside collection. I'm posting here in hope that someone might have some information of it's origin.

The deck is one solid piece of timber & the wheels are made of clay. According to wiki, PU wheels were introduced in the early 1970s.. so is it plausible to think it dates back to the 60's?

Any information on this would be much appreciated.
Cheers!

Take it to Darkside - Mark or someone who knows will probably have one similar with history.

I have one like it too, which also came from a similar situation / find. They are interesting to see, but there are still so many of them that they are not worth any $$$ more so just the curiosity and interest factor.

cheers Mark