Could There Be Silver Coin In The Malaya 1948 King George VI 20 Cent?

According to Numista records there shouldn't be.



But I came across one that doesn't look Cupronickel. Below photo shows the #1 1950 CuNi 20 cent, #2 1943 0.5Ag 20 cent, #3 the aforesaid 1948 20 cent.



I did a frequency ping test with Bullion Test Free (which gives the peak resonances) and Precious Coin Tester Apps (which gives Silver ratings). Results summarized in table below.



As you can see the frequency of the said 1948 is nearer to a Silver coin than a CuNi one. It also score Good when the Rating App is set to 30% Silver. One issue is that it weighs about 8% lighter than standard 5.43g which may be attribute to the heavy worn down. I do not know anyone would be counterfeiting a common coin as such. I also went the extra mile to perform similar test for another different set of the 3 coins. From the table, results are consistent with the expected materials and coin dates.


Frequency plot for Coin #1 1950 Twenty Cents


Frequency plot for Coin #2 1943 Twenty Cents


Frequency plot for Coin in question #3 1948 Twenty Cents

I read that some coins during the transitional phase from Silver to CuNi could possiblity of planchet mixed up. Is there this remote possiblity, I have never heard of for Malaya Coins. How would one be able to confirm? And if that is indeed having some Silver content, would it be a valuable find?



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