The 1953 Lithgows are rare, but I'm not sure they bring a premium over any other AustralianMk III. They were the last of the 1000 produced at Lithgow as machinery and tool proofing. I've not seen another since buying this one.
If I had any business sense in me, I should have bought as many as I could have afforded. They were cheap and plentiful back then, and I thought they would always be cheap. I was young and dumb!