Front Forks

Can anyone help me re the front forks on this bike? The previous owner didn't have dust seal on the top of the forks, just rubber concertina covers that he fitted. That's strange to me but what I really would like to know is why the front forks don't have casting to fit the front guard to. Other TA's have two threaded castings on each fork to take the mounting bolts. This bike has smooth forks, any ideas?

Thanks