If you happen to get a set of regular FL dies that were first up with a new reamer, they may actually be "Small base" dies. Just no guarantee. If the reamer is a bit worn, it might be a few thousands over minimum, but still below maximum SAAMI dimensions.
Actually you have that backwards. A new reamer is at its largest and will cut a maximum sized hole. They wear smaller and are also smaller after sharpening unless the sharpening is done by setting the grind back.
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