technically correct, Josh, gap filling is a reference to the chemistry of the adhesive, but in general, gap fillers are more viscous (10000cps+) than regular CA (<100cps).
But in a pinch, if you need something a bit less tricky to work with, the gap fillers will work just fine with or without a gap, they just won't penetrate as far into a fine gap.
I do notice that Loctite has a version of regular CA (chemistry-wise apparently) that is a gel. I used it recently and found it very easy to work with, and it has a bit of a tack time before hard setting, unlike regular CA. But it doesn't claim to be a gap filler at least on the label, so I would imagine it falls in the "thick" regular CA category. It is cleverly labelled "Super Glue Gel".