I presume you are asking if common sterling and 50% silver coins were ever counterfeited.
There are a few occasions where very common silver coins were counterfeited to make a profit. One of the most interesting and prolific was during the 1893 world silver glut when silver prices dropped below 30 cents an ounce for the first time in history. At that time, it became profitable to copy most circulating silver coins to make a significant profit as long as the counterfeiter could produce decent dies. A typical dollar coin contained less than 1/4 of the face value in actual silver value. Spanish 5 Peseta silver coins, for example, were targeted in absolutely enormous numbers. The counterfeits are very close to full weight silver because the counterfeiters could double their investments as fast as they could produce the coins. Millions of copies were made and circulated unnoticed for the most part.
In the US, at this time, the targets were common Morgan dollars
and Mexican 8 Reales made for export to China. In Peru the Sol was targeted and similar things happened elsewhere. In the 1930's the price of silver dropped a second time reaching levels as low as 1893 and the counterfeiters produced silver counterfeits for a second time. By this point in time fewer countries made large silver coins but those that did experienced a boom in counterfeiting.
Silver counterfeits are often difficult to identify unless the counterfeiter makes a mistake on the dies or in how they make the coins. Improperly applied edges are often the best clues.
There is a second clue that is useful. Because it is very common for a counterfeiter to short the assay a bit to increase his profits further. That is because a quickly run density test (or a coin scale based on weight and size) is unlikely to disclose a 15-20% silver shortage in a 900 fine silver coin. So, these made for circulation silver counterfeits can run slightly low in silver content which makes them detectable by performing a very accurate density test.
There is a third counterfeiting method involving common silver coins that happened in the late 1960s and early 1970s. This is the time period when silver coins were being quickly withdrawn from circulation because intrinsic value rose above face value. There was a market opportunity to add to the bags of collected coins a percentage of base metal copies to inflate the value of the bag. The reason was because the people gathering silver coins at face value rarely looked closely at the coins and NEVER did SG or magnet tests to scan for fakes. I know of this happening in one instance involving Peruvian Sols - the 50% silver type. The counterfeits in this instance are magnetic and come in a wide range of dates including the Scarce dates of 1930, 1931 and 1933. I own several examples of all of these Sols that are worn to VF-EF range and are highly magnetic. I own one example in an NGC
holder that is so magnetic that the coin and the entire holder can be picked up with a magnet. As we all should know, any alloy of 50% silver and copper simply is not magnetic. In fact, there is no metal alloy made of 50% silver that can possibly be magnetic. So, testing all 50% silver Sols and 1/2 sols of types that were still circulating in 1965 can be identified as being counterfeits if they are magnetic. These were produced to defraud bullion traders in the late 1960's and 1970's. I classify them as Contemporaneous Circulating Counterfeits, but I would not object to people calling them Numismatic Forgeries instead.
My book on Counterfeit Portrait 8Rs is available from Amazon https://www.amazon.com/Counterfeit-.../1500497177/
or from me directly if you want it signed.