You are not even sure if there is a dent to begin with, hence the use of a "?" in your statement, and then you wax on about how ABS isn't durable.
Acrylic is a nightmare when used for universal shells.
Acrylic is hand poured into a mold, and is exposed to UV light to harden. The results of this process is never consistent. Shell wall thickness will vary, along with color as well. It is a messy process, time consuming and as a material is not as strong as ABS either.
Due to the fact that colors will often vary, if there is a need for a repair, both sides need to be rebuilt in order to insure that the colors match. Speaking with experience
ABS is a far superior material to use when compared to acrylic for this application. I can literally stand on our shells, and they will not break, shatter etc. an acrylic shell would not survive that type of abuse.
ABS initial costs are expensive, engineering fees, drawing/drafting, having the "tooling" made (molds), cost can exceed $20,000 for a shell design.
A mold for a hand poured acrylic shell may run about 10 Cents to 3$ in material costs. (depending on the colloid used).
Over the years, I have used both acrylic and ABS, and while acrylic is used by several companies to build universals probably because it is cheaper process, I prefer ABS due to its superior durability, and consistent results.