If you need to mass produce something and you “only” need to give the part a nice grip and not something that is strictly identical to SLS, then I think adding the grip before printing is worth exploring. It will save you a lot of time compared to post-processing each parts.
Changes in geometry due to printing directly on the BP can be dealt with. In the last version of preform the first 0.75mm of the part will have identical layers (more details here), BUT the squishing might take care of that almost entirely. The squishing will ultimately depend on the Z offset value and total surface area of the first layers but it is repeatable so if you want to add some material on the 3D model and have it not be visible in the final print, while saving the actual useful geometry, it is possible.