Yes, they would, it tracks all BT devices, not just Airtags.
But even with an unmodified tracker, it's quite hard to locate one in a car, because there is a lot of hiding spaces (especially if you put one in some hard-to-reach space such as under the carpet in the cabin etc...).
Using randomized or rolling addresses avoids detection to an extent, depending on how many randomized addresses one uses and how often they're rotated.
However, it's also trivial to detect randomized (or rolling) addresses due to the address being utilized for more than a single locality. Although, I'm not sure that either Apple or Google is actually doing the randomized detection even with this new patch.
But even with an unmodified tracker, it's quite hard to locate one in a car, because there is a lot of hiding spaces (especially if you put one in some hard-to-reach space such as under the carpet in the cabin etc...).