If you are looking to develop a commercial product, the R200 in the Robotic Development Kit may not be the best choice. This is because it is a retired product line and so it is uncertain how much longer it will be available if you need multi-year supply of it. It is also the oldest of the currently available RealSense models, so its tech is out of date.
Furthermore, the cased USB R200 used in the Robotic Development Kit is not suitable for commercial purposes, as it has a limited-duration warranty. It is preferable to integrate a caseless Module Kit circuit board version of the camera into your product. The easiest way to obtain the module version of the R200 is in the Intel Aero Vision Accessory Kit for drones. Again though, it is unknown how long this product will continue to be available to purchase.
Also, the accuracy on the old RealSense cameras averages +- 5%, whereas the 400 Series cameras average 1% or less. At close range though, you may need to alter the scaling factor of the camera to get the best results.
For accuracy, latest vision technology and long-term future proofing, and image quality, the 400 Series Camera may be the best choice. It is planned that in 2020, a next-generation D600 will be introduced that provides an easy upgrade path from the D415 / D435, meaning that it should be straightforward to upgrade your product.
If the holes that you are going to be scanning are in a fixed position, the D415 may suit your needs, as it excels at scanning static objects. It is also currently the easiest 400 Series camera to obtain, as the D435 ordering process is currently backlogged due to short supplies, whilst the D415 is available to order today
If you anticipate that the holes or the camera will be moving, the D435 is the appropriate choice. Due to the aforementioned short supplies, you could start prototyping with D415 now and switch to a D435 when the supply situation improves.
For the final version of your product, both the D415 and D435 have caseless Module Kit circuit board versions with varying configurations denoted by product numbers (e.g D400, D410, and D415 for the D415, and D420 and D430 for the D435).
A further configuration option that may be available to you may be to use a custom RGB sensor other than the default one used by the 400 Series, so that you can get a more industrial-level quality of sensing than the default sensor can provide.. This can be attached via a custom made 50-pin cable to the Vision Processor component of the camera's circuit board.
The data sheet document linked to below contains the technical details of the 400 Series camera and Module Kit range.