It's possible the petty theft charge is the reason for the 3 day delay. You will probably have to live with it, especially if it resulted in a court decision. However, there are cases of mistaken identity that occasionally cause a problem. Defferent individuals with same name, age and race, birthdate etc. any one of which may cause a problem. As a Wisconsin resident you are only cleared through NICS on long guns. The Wisconsin Department of Justice is the Point of Contact on handgun purchases, NICS doesn't get involved. You were unclear if your purchases as a Wisconsin resident involved long guns or handguns. If they were long guns and the delay was because of the NICS check you may be able to get some info from the following:
ATF Tracing Center 1-800-788-7133 or NICS Customer Service 1-877-444-6427 Option #6. You may or may not get a satisfactory answer to your request. Remember, this is our anti-gun government at work.