They usually do not have the OE broadcast code stickers on them. Also, many aftermarket chips have a label with the vendors name on it.
If your 1-to-4 light still comes on and the fan strategy is as listed in the Service Manual, you likely do not have an aftermarket cal.
At this point, some of the best aftermarket cals come from Marc Haibeck. I think, he advertises on the Registry site. He has a web site at:
www.zr1specialist.com