Most forensic firearms examiners in our state would testify that a muzzle device was present. Given that state law fails to actually provide any technical guidance for what qualifies as a muzzle brake or a flash suppressor, most crime labs in our state have taken this approach. Also at least with my dept, we dont testify to what is legal and what is not. We will testify about features present on a firearm, and the matter of legality is left to the attorneys and or jury. A few disclaimers, forensic firearms examiners are a type of forensic scientist that work in crime labs, and the vast majority in this state work for accredited crime labs. The training for folks in these positions typically lasts between 2.5-6 years and there are actually very few of us in the entire state (think about 30 for all of NYS outside of NYC). What makes things tricky is that you dont have to be a firearms examiner working for a crime lab to be considered firearms expert. We have had gunsmiths, gun dealers, police dept firearms instructors, swat guys, and the dept "gun guy" all attempt or actually testified as a "firearms expert". Some of these folks are very good, others have had no clue at all. Who is allowed to offer expert testimony is really up to the judge in most cases.
As someone who spends lots of time testifying in court about firearms I would simply say this, until NYS provides clear legally binding clarification to technical issues related to safe act, the answer is we dont know.