Ah, that makes sense. But topquilts, besides not being differentially baffled, are typically narrower than underquilts, which could present a problem if you’re using it in a two-person hammock.
What temps are you looking at? You might want to consider making something similar like a surplus poncho liner UQ.
To answer your original question, btw, no. There aren’t any top-quilts out there that are better designed for use as an underquilt than others (although obviously sewn footboxes are a total no-go). I had HammockGear add an extra pair of grossgrain loops to the head of my quilt to make it easier to attach, and you might consider doing the same, but topquilt baffling and underquilt baffling are designed to serve different needs.
So long as you’re well above the temp rating, it doesn’t really matter. But a 20º topquilt used as an underquilt in 20º weather will make you unhappy.