The one significant thing you're leaving out is that you're not an expert. The person who made this call supposedly was.
Not the OP but an expert can only be as good as his training/judgment/experience AND the quality of the exhibit.
If they only had one best, usable frame to go by, I get the impression it's not ideal, as far as quality. That's going to require some guess work.
He's not on trial (unless AT brings it there and don't think she will, it's only useful to her now, to discredit and toss), but I'm sure he could explain how he arrived at 2011-13 in the first place. Something he saw or thought he saw. Maybe elongation or a shape but again, it's not like he's comparing different-year models on a showroom floor.
LE has linked that same car to known occasions with BK at the wheel, likely tying it to innocuous driving/parking to show this IS the car, he drives it, and look how it appears on CCTV even when we know it's the exact car.
When investigation produced an actual car for consideration, the absolute correct step is to say could this car be that car in the photograph/frame/video? If it can't be excluded, then you expand the years.
The bulk is different but to me it's no different than if LE identified a perp, from cctv, as wearing a maroon sweatshirt with stripes, but when he's located, turns out it's a maroon sweatshirt with lettering. It's just a matter of clarity. Nothing trumps seeing the suspect vehicle (or photograph of it) for a side by side, point by point comparison.
To me, it's most important that LE has cctv in the first place, that it was good enough to get make and model correct, and they have an actual car to compare it to.
Even if the video mapping is imperfect and incomplete, it tracks to Moscow. Laid next to his DNA having been recovered from the crime scene, that makes for synchronicity, something IMO jurors like.
If his DNA is there, how'd it get there? He drove it there.
JMO