the surface texture could also just be the layers.
No fdm 3d prints is ever smooth coming off the printer.
Remember that you are printing with a cylindrical bead. so the edges never match up exactly.
Think of it like a the way a log cabin is built. Always indentations between the layers of logs.
FDM 3d printing is exactly like that, just with really really tiny logs :-)

Makes you wonder why nobody has yet made a square profile nozzle.
For certain builds, that would be really useful.

Also pictures help :-)