Backup plane for checkride: Can it be a different model? 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 &quot;Airman Certificate and/or Rating Application&quot;, 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 (&quot;I'm a Designated Examiner. I noticed a mistake when reviewing the IACRA application....&quot;):

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?
I came to the same conclusion as you, I don't see anything keeping you from going. You meet the requirements of 61.107 and 61.109, you have recent experience in both aircraft, and as far as make and model, they're both PA-28's. That's like going from a 172B to a 172S: it's the same make and model, Piper just makes it a little less obvious with their nickname and number combinations. If you had trained in a Warrior 160 and an Arrow, it would be a bit different, but only as far as requiring an additional endorsement.