No, there is no such thing as the 'new' shipments. All products at Apple are either updated or refreshed every quarter, all manufactured iPads will most likely contain the light leak issue, since it was produced in the first quarter of 2011, which is what the 'F' stands for. For example, if Apple fixes the light bleeding, they will do so in the next quarter, which would presumably be in June or late May and include a new fourth letter/number of the serial number. You may have gotten lucky by not having any light leak issues, but saying that all iPads are now 'fixed' is obscure. As I've said in my previous post, even if you go for a replacement iPad now, you're 80% likely to have the same issue.
Only thing to do is wait for the new shipments to arrive presumably in the next month or so. Also, could you provide a source on where you got your justification that "replacements via AppleCare are now fixed"?