It comes down to 2 subjects- money and performance.
GM is now giving some hefty rebates due to the economy. If the GTO is not on the rebate list and you are in competition with the "must have" crowd, you may not even get a break on the sticker. Remember the PT Cruiser, the first year they were going at what the dealer could get. Being placed on a waiting list and paying at or above sticker is not my cup of tea. The second year out, the car is just as nice but the sales are starting to plummet. Rebates are in force and dealers are happy to bargain. Now, the PT has turbocharging which really helped the performance. If you can wait, you gain control. Unless the economy soars and people start snatching everything up on 4 wheels and come to their senses and buy American. If all these conditions are in place, go buy a lotto ticket.
Performance? The car will be tweaked to correct any minor flaws. Maybe another color, different interior appointments. But I don't think anything big because the management will be studying the returns (sales) throughout the year. Nobody sticks their neck out too far these days nor is their a ton of money for development.
The switch to American manufacturing? I'll let those members who know the business answer this one. I would guess that the plans would already be in the works regarding where and when to build the car. The lead time must be measured in years since it is a big undertaking.
My own feelings. If it isn't manufactured in the US, then the GTO, however good the performance, does not truly represent the car. Might as well make it in korea or Japan.