Campaign rings and unit emblem rings as you said are easier to produce and hard to detect from originals because they often are made ( and engraved) by hand. These rings are supposed to be made by soldiers or locals. Look at the WW1 trench rings made after the GreatWar..they are memory rings ( in their way accepted authenticals but not trench made); indeed hard to detect.
The repro Kreta ring has a more industral engraving; interesting to see how they tried to copy the writing if I compare.
Thanks for the pictures and info Gaspare.

Benten