Yes there are pro cuts of actual players with +0 . Forget about that for a second.
Back in the 90's did you honestly ever see a double tagged jersey for sale in a store? I never did. Champion even wasn't making retail authentics for every team yet. Tim Hardaway was traded to the Heat in Feb 1996. The next season was the 50th anniversary gold logo year, so there was only a small window for non-gold logo tim hardaway jerseys to be produced. Plus Champion never started churning out authentics mid-season of a traded player.
How come Harold Miner jerseys, which to my knowledge is the only retail authentic heat jersey champion made, don't have the double tags?
The only plausible explanation to me is that most of the double-tagged authentics are actually blanks that were customized, probably by the pro-jerseys guy who runs a customization business.
http://www.pro-jerseys.com/aboutus.asp. I bought my stockton jersey from this seller and they were definitely selling the double tagged A.I.'s years ago. I have seen retail authentic rookie A.I.'s with the gold logo and the number placement is noticeably different on the double tagged A.I.'s on ebay.