1916 Mule Halfpenny

Thanks, and are there fakes out there? How would you spot a copy or fake one.
I read a thread on a fake on up for sale but how would you tell

One could, in theory, make a fake mule by taking two normal coins - one 1916 Australian halfpenny and one Indian 1/4 anna from the George V period - and destroying them. Use a sander to grind flat the unwanted side of one of the coins (say, the reverse of the Indian one) and then use a lathe to hollow out the unwanted side on the other coin, leaving a shallow bowl the flattened remnant of the first coin can fit inside. Magicians use this technique to make double-headed and doubled-tailed coins; see this thread for some American examples of such coins, and for illustrations on spotting the telltale seam.

We'd have to see the other side.

There is another possibility for making the 1916 mule. The Indians restruck a number of coins in the 1960s for collectors using old dies (such as the pennies and halfpennies from WW2). So that means that not only did they retain old dies but they saw the money making potential.
For all we know an enterprising mint curator (a David Gee wannabe?) could find the old dies (unless they were destroyed) and make a few more mules, maybe even make mules that never existed such as Raj era dies paired to Republic of India dies.

A two half, joined - together fake mule could be easily revealed by ring tone.

UPDATE
Mr Ts references to the Calcutta mint closing and transferring dies got my brain trying to remember details about the Mint.
I keep an extensive cross referenced book of references (and again I admit to being anal). Found a reference to the Calcutta mint in the Australian Coin Review (Jan 1968 pages 5-6).
It was a first person account of Allan Gally and his report first appeared in The Canadian Numismatic Journal. He toured the Indian mints and noted that Calcutta mint had 50 presses and Bombay 40 and they use 120,000 dies a year.
There seems to be errors in the article as it references the old building being built in 1824 (and the Calcutta Mint website confirms it closed in 1952 and a new mint opened nearby in Alipore).
The interesting part was this paragraph:
"A section of the Calcutta Mint is
put aside for the striking of
'genuine' coins for anyone ordering
them. Working punches and dies
of coins that have ever been struck
by the Indian Mints are stored
there and, for a price, anyone can
have a rare coin. These restrikes
are sent all over the world to any
collector requesting them. At one
time, the Mint struck early Aus-
tralian coins (they originally struck
these for the Australian Govern-
ment, hence the dies were on file),
but the australian Government
raised such strong protests that
India returned the dies to Aus-
tralia."
Then the article goes on about the problem of counterfeiting in India. Then another interesting paragraph.
"A quantity of the counterfeit
coins have seemingly been struck
from original dies that must have
been smuggled out of the Mint at
one time or another. A display
cabinet contains over 200 pairs of
dies that have been confiscated
from counterfeiters."
As the article references the return of dies to Australia (and that was in the 1960s) then if only the 1942-43 dies were returned what happened to the 1916-18 dies? and if they still existed in the early 1960s (when the restrikes happened) then why didn't a collector request restrikes of them as well?
So did nobody think to request them, or had they been misplaced (easy with that volume of dies over many years).
Perhaps someone in Canada might have access to the original CNJ article to see if the ACR editor added erroneous details?