It is not a question of faking - just the continued production of popular product designs. If a book list "Classic Czech Perfume designed 1932 and still in production.", you can be certain that it will be offered on a stall as Czech 1932. Most price tickets are quite small and it would be very hard for a dealer, particularly with cold fingers in the morning air behind his stall, to write a lenghty description and still leave room for the price. Of course in some cases, the books also economise on ink and only leave the design date - it is only human nature to suffer myopia in such cases. Older is better than new!
The same phenomenon happens here on the GMB when literacy challenged dealers are told that their treasure appears in a 1906 catalogue, the explanation might then continue at length with why only a limited production was produced at that time with the mould being rediscover 90 years later and production restarted. On eBay it becomes 1906. The dealers was looking for the answer to 3 questions Who, When, What is it worth, they have no time for more.
This begs the question is older better than new? Not always, sometimes the quality of materials used is better in modern times. But also it should be the aesthetic of the design that is valued, a hypothetical date of production is largely irrelevant in that respect. It might be that particular colours were not produced beyond a certain date, or introduced at a specific date. The collector as opposed to investor is often valueing these minor details more than the actual age. Items that are in production for decades are no longer uncommon, perhaps collecting ideals that grew in an age of more handmade goods are themselves in need of change. But while collectors are treating the modern production, perhaps even continuous production, of classic designs with disdain then the dealers will certainly cater to those whims. Only the specialist dealer will have sufficient knowledge to sort his stock of pressed pink "Pandora's box" into its 8 decades of production. The general dealer will ever stick to 1927 as that is what it says in 'The Book'