Key to this case will be the intent of the law. Did Congress intend to prohibit "straw purchases" to keep firearms out of the hands of prohibited persons; or did Congress intend to prohibit "straw purchases" in order to track/trace firearms owners?
If the intent is to keep firearms from prohibited persons, then any subsequent transfer to a lawful (non-prohibited) persons should not be illegal. If SCOTUS determines that the intent is/was to track/trace gun owners, then Abramski's side is in trouble.
In this case, it is important to note that Abramski didn't just take money from his uncle and then give him the pistol. Instead, they visited an FFL to conduct the transfer. The uncle filed out a 4473 and underwent a bg check before taking possession of the pistol from his nephew.
This is what the NRA calls a "check-box felony." Never was there any attempt/intent to deliver a firearm to a prohibited person or subvert the bg check process. Indeed, both the initial transferee (Abramski) and the secondary transferee (Uncle) both underwent the bg check/4473 process via a FFL.
In the Abramski case, the nephew was gifting partial value of the firearm to his uncle. As an LEO, Abramski qualified for the reduced pricing offered by the mfg (Glock). He was passing along these savings as a gift to his uncle. Without the gift of partial value, the uncle would have paid full retail value for the pistol (approx $550 at the time when Abramski acquired the Glock at $400). Again, both parties underwent the bg check/4473 process via FFL at each transfer during the process of Abramski gifting the $150 discount to his uncle.
Given that both transfrees underwent the 4473/bg check process, even if Congress's intent is/was tracking gun owners, the intent of the law was never jeopardized in this case.