Hello Dave
Yes, arguably Australia's best reel mower.
Yours would be 1962 or earlier, I believe.
Most likely 1950s - given the serial number SC01555.
['SC' stands for Super Cut].

509X is the Villiers (Australia) specification.
This has a Ballarat-made engine.

The flywheel should have a date stamp ...
[Linked Image]

For topics on your model, type 'Model 17' in the Blue Search Bar (above).

Do you plan to restore this machine?
They can be used quite effectively on residential lawns,
and, of course, can produce excellent results.

Hope this helps.
---------------------
Jack

[Linked Image]

https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/64309/MODEL_17_-_History_Record_-_Th.html
https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/71423/CATALOGUE_-_Full_Range_-_c1963.html