Picasso's "Dove In Flight" on China (PRC) #108-110

Just to clarify, the reprints for this issue still have decent value -- $28 in 2019 Scott. The originals in mint condition catalog at $70.

What you really need to watch out for is the reproductions for many of the PRC issues through the 1970s. If you are only looking at the color/design, the reproductions are quite good. If you don't have the stamps in hand, you can't tell the difference in paper/quality from the pic. However, in most cases (especially the pre-1970) issues, you can spot non-originals/reprints immediately by looking at the perfs. If you are familiar with the set, you will be familiar with the quality of the perfs. If you look at the Picasso dove set above, you can see the perfs are rough with numerous fibers at the tips of the teeth. The degree of irregularity and fibers will vary from issue to issue, generally improving over time. On reproductions, the perfs tend to be very uniform. It's easy to reproduce designs & colors accurately now. What's difficult is the paper, and even more difficult is the perforation on poorly perforated issues. Getting the perf gauge correct is easy, getting the perf shape/size/roughness correct is really really difficult.

I've seen so-called souvenir collections in books that are nothing more than reproduced stamps. These are not the original gift shop souvenir collections sold in the late 1970s and through 1980s -- those actually contained genuine stamps. Many of the souvenir collections on eBay are knock-offs with reproduced stamps. I haven't checked in the past couple of years, but some people would break up these fake souvenir collections to sell the stamps individually to unsuspecting buyers.

One of the advantages of having a genuinely postally used early PRC collection is that one can see what the genuine stamps really look like. But almost nobody collects used PRC from that period -- they all go after the unused stamps. With the speculation going on with PRC stamps, it's ripe for forgeries/reproductions.