I'm a student pursuing a US Private Pilot License, and recently scheduled my checkride. I've been training in a 1981 Piper Warrior (PA-28-161), but if its annual goes sour I may have to take my club's 1980 Piper Archer (PA-28-181). I have well over §61.109's 40 hours in the Warrior alone, and only ~10 hours in the Archer. I have a separate club checkout and CFI solo endorsement for each, they're pretty similar anyway—they're even both the same ATC type (P28A)—but they aren't the same model.
Here's the catch: Form 8710, the "Airman Certificate and/or Rating Application", asks specifically for
[II.A.2.] Total time in this make/model and/or approved FFS or FTD (Hrs.)
Furthermore, according to the IACRA FAQ ("I'm a Designated Examiner. I noticed a mistake when reviewing the IACRA application...."):
A mistake in the applicant's information cannot be corrected after it has been signed by the Recommending Instructor.
My prospective DPE explicitly told me that the backup plane was fine, and I can't find any Part 61 regulations that are specific to experience in one make/model aside from adding an experimental aircraft as part §61.63(h)(1), which is what I assume the box is really for. Of course I'd rather test in my more-experienced plane, but I'm asking specifically for regulations here if Plan A falls through.
Are there any regulations or headaches that I would encounter if I need to change the tail number or model number of my checkride plane and listed hours therein, potentially long after IACRA submission?