On-topic as a question about U.S. patent law and procedures.
I do not see any distinction between antedating a reference on a "regular" 35 USC 111 national application and a 35 USC 371 national stage application. There is an MPEP page that covers the differences in how these types of utility applications are treated. MPEP 1896 It does not included anything indicating that 102(a) is viewed differently. And I'm sure the overall criteria for basic patentability couldn't be different.
Explaining the "Patentese" of the question and the answer
For people who are not up on all the ins and outs of U.S. patent law let me say this all again in "English". A national application is a non-provisional utility application filed directly with the USPTO. The applicant could be from any country. A national stage application is an application that was initially filed as a PCT (Patent Cooperation Treaty) patent application. A PCT application can be filed by anyone from any country and is usually filed "internationally" by sending it to the home patent office of the applicant's country of residence labeled as a PCT application, but can be sent directly to the International Bureau in Geneva.
While there is no such thing as a granted international patent, the PCT process is a way to simultaneously file an application in some 140+ jurisdictions with one set of paperwork in one fell swoop. When you file a PCT application, unless you opt out of specific countries, you are filing a US application, a German application, an Egyptian application, etc.
Sounds great and it is great but there is no such thing as a free lunch. The "applications" in all those places will die by a deadline, unless an opt in (and pay money) occurs in each place you ultimately really want to continue. Then the applications are pretty much treated as per local laws. At the time you opt in to a country you are not doing a filing. The filing was the PCT application. You are just "entering the national stage" of that application in that country. In the US patent law section 111 governs a regular application and 371 governs applications that get into the US patent system via the PCT process. There are some small differences in how they are dealt with due to details of the Treaty. However, the requirements for patentability are not different.
The original question had to do the with the case that prior art is cited by the examiner and the date of the reference is before the filing date but after the inventor actually invented and reduced the invention to practice. A way the inventor can try to deal with that is by submitting a section 131 affidavit. In that submission there is a sworn statement from the inventor and preferably from witnesses, also supporting documents, establishing a date of reduction-to-practice that is before the date of the reference. It is called "swearing behind" the reference. The party who may have written the reference in question is not involved. If the examiner is convinced then the reference is excluded as prior art. The USPTO does not do any independent investigation of the facts.
As explained above, if you convince the examiner you get the reference taken away. However it is a dangerous way to get past a reference because it creates a potential vulnerability to the patent that may be re-visited in court some day where there will be another side doing investigations, taking sworn depositions, etc.
Of course under the AIA first to file law in effect for things filed March 16 2013 or later, swearing behind goes away. For those applications it no longer matters when you invented it.
