for one thing, the Aurora has GTO molded in little letters down low on the front fenders. another is that the Aurora's grille has a lower chrome section down low in the bumper, where the JL's doesn't have the lower section and has the insets in the bumper painted black. The Aurora's grille has what looks like a "+" in each large section, where the JL doesn't. I have a blue Aurora GTO in nice shape and the corresponding blue JL pullback, and I actually use this as an example when I'm showing the non-initiated my hobby... I let them look at the two side by side and point out the differences.
In general, I think the Auroras have lots of tiny little sharp details that the repops don't possibly because they were molded in cycolac instead of styrene or whatever they use now...
--rick