Did one of the caps fall off? If not then yeah I'm dubious. Mine taking a photo of them?
Edit:
According to:
https://www.down4soundshop.com/sundown-audio-sa-classic-series-12-d2/
"These are basically identical to the "v1 / Rev3" SA series but with a black motor (so, yes, you can mix them). We received an outpouring from fans of the "original" SA with the release of the full v.2 model so we listened and have brought this model out to fill in at that price point!"
Also on their website:
https://sundownaudio.com/lv/sa/subwoofers/sa-series/
"Here at Sundown Audio we take feedback from customers and dealers seriously. With the launch of the SA v.2 woofers we heard a lot of call to also keep the old version for lower depth / lower cost applications — so we did that via the “Classic” SA. Still available in 10s and 12s it is essentially the SA v.1 Rev.3 but with a black motor finish. We even squeezed in an upgrade… the motor is bolted together for enhanced long-term durability! "
Eh, manufacturers know what they're talking about, I wouldn't sweat it personally.