I'm no expert, but...
I can understand why you wouldn't want to post the photos of your artifacts here. It's a sound decision to keep artifacts guarded as certain cultures have laws that mandate the return of important artifacts. I've studied Egyptian and pre-Columbian history a great deal, but only as an enthusiast and not as an academic. I don't know if I can help, but maybe I can give some direction to help you pin it down. Many figurines from ancient South America often represented deities, priests, or kings (and sometimes kings and gods were one-in-the-same). An effigy of a priest might shed some light on its origin because priests had different functions in different cultures. The Incan priest, for instance, would oversee the celebration during a voluntary self-sacrifice suicide of their subjects, whereas Mayan and Aztec priests would carry out homicide sacrifice exacted by their own hands. The details in clothing of figurines wouldn't be very dissimilar from one culture to the next, although Inca had a heavier clothing for living in higher climates. Smaller details such as weapons, jewelry and, hopefully, glyphs would narrow the origin down better. Simpler writing began with the Incas and was absorbed and evolved by the Maya and later, the Aztecs, so picture-glyphs are a great indicator. Indiana Jones, for instance, had to translate Oxley's letter in a dead Peruvian language by walking it through Mayan first. I can't translate, but I have several books that may help to identify certain symbols. Without asking for photos up front, would you mind describing a piece or two to me?