Real Silver Coins Or Fakes?

They look fine to me. Proper weight is 28.2759g. The variation may be down to your scales - many cheap modern scales fluctuate in their readings quite a bit.
Also to test the silver, you are better to find a jewellers with an x-ray machine as then you won't damage the coin. They should be able to tell you the percentage of silver in your coin - if they are silver, then that is good enough as the value of these is pretty much the silver content only as they made a great many of them.

oh and

I've got one of these crowns in its original packaging that I was given by my parents in 1977 when I was a teenager. Yours look identical to mine.

to the Community!