Yeah. In theory, everything is customizable because, even when you can't do it in Daz, you can go to another software (like Blender for meshes and Photoshop for textures), but some customizations are easier than others. Don't think, though, that using only dials is always an easy way out. For characters, for instance, if you just want to change a minor detail, it'll be easy, but creating an entire new character with dials to the point people will recognize it as custom (that is, "never seen before") and also looks good it's something that takes a day or more (depending on your perfectionism). Poses are another example -- and, since most of them are made for the base form (the Genesis whatever number), the more your character departs from the base form, the more you have to adjust it (and posing is something you basically only deal with dials -- and it takes a lot of time). And, sometimes, going out of Daz is something that is overhead.
In the case of the firefighter helmet, It's an easy customization (for those who have practice with some photo editor like Photoshop or Gimp) because, as you can see in the promos of the asset, there are many variations, and when you look at the photo of the clay render (without textures) you can see the surface is flat. When there's some relief, one would have to go to a software like Blender to modify it or erase it, but since it doesn't, you just have to create the textures which, in this case, is not even a complex texture, so you just erase the number and add another one (and it doesn't even need to be the same typeface). But I don't think this would be necessary because, unless there's some hidden meaning in the numbers, any number would do. In fact, in scriptwriting theory, the recommendation is to not add any relevant detail unless it means to the movie (or TV show, or novel, or whatever). So the fact he uses the default number is a tell that it means nothing; if he had changed it would either be a tell that it means something or create a red herring which, if it were unintentional, would be a mistake.
On the other hand, in the case of the security guy's uniform, I think it was a mistake because the NYPD badge conveys more information than a mere number, thus it either creates the idea that NYPD has some meaning (which is a little absurd since he's a security guy in a college) or that it was some sloppy design, an oversight. So I agree with you on that matter. But, of course, since, on the whole, DPC is way superior to the vast majority of the other devs, it's excusable (even more when it's something that happened in season 1). And maybe (since he codes a lot and likes to do mini-games) DPC came from a coding background and not a graphic designer background, so he wasn't (at least, back them) acquainted with Photoshop and used to customize materials as he was with coding so changing the badge would be too much without hiring someone... (And, even today, he does little customizations for material or textures; the most notorious one being the HOTs' uniform which, in fact, is just the colors of one of the default materials with the inscription "HoT" from another, with a cyan detail on the side which can be done inside Daz; most of his customizations were like this -- coloring).
We have to keep in mind that, when you do a VN (adult or not) alone, it's like doing a movie or a TV show and you have to be the director, the producer, the screenwriter, the cinematographer, the editor, the sound designer, the costume designer, the architect and props maker, and even an actor by proxy (and, even when you don't create the assets yourself, which is most of the cases, you have at least to select them; something that, when well done, also takes a lot of time). Thus, it's a lot of work and everything you can do to save time is a rational decision. Because, even if customizing the firefighter's helmet would be easy, if you start to do this for every element in the scene, the time spent will add up, and you'll end up spending a month or more just customizing them. So, yeah, in an ideal world, everything would be custom-made like in Hollywood movies, but in the world of AVNs we have to select what matters and let the rest go.
