These are not so much counterfeit pieces (because they copy no real pattern), but rather toys. Alas, unscrupuous antique dealers often try to palm these off as "vintage" pieces. They often site the flowing blue decoration or glaze crazing as proof of their age, but it more closely reflects that such pieces are truly cheap imports. They must have been made by the shipping container full, as they exceed the level of common. This set includes a number of pieces but all of it is just as fake. They truly have NO value, except as toys or to dupe the unknowing.
Curecanti Pattern
Curecanti was reproduced in the mid-80's. Besides the fact that it looks too new, they have a modern Sterling backstamp. Sterlin never made the real wares - only Syracuse and Bauscher made authentic Curecanti.
Prospector Pattern
FAKE Logo<::><::><::><::>
REAL Logo<::><::><::><::>
Some reproduction or counterfeit plates were made in about the 1980's. While the backstamp ought be a easy give on these, the style of the logo is a give away if the back can't be seen. Pay attention to the "wings" of the speed lettering and the poor subterfuge becomes obvious.
(Note: The use of the word "counterfeit" to describe this china is not meant to imply that it is "good" or "bad" - for our purposes, the intentions of the counterfeiters are irrelevant. Authentic dining car china was made to be dining car china, counterfeit china was made to look like dining car china. Well done or not, it is not authentic dining car china, and if it is not clearly marked as a reproduction, then it is counterfeit.)