Several of the more obscure older B&O patterns (like Montclare, Strata Dome and Garrett) have been counterfeited. If you wish to avoid counterfeit items, do not buy any pieces with a Homer Laughlin, BTC, or modern Hall China backstamp (the modern logo is television shaped - flat on sides, curved top and bottom).
Cromwell pattern silveware
The B&O Musem had a batch of reproduction B&O Cromwell silverware produced (along with silverware from other RR's). The telltale sign is a large number "1" or "2" stamped on the back of the handle.
(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.)