I agree with doggg1. I've bought boards for 20 years and I want to visit a board house and assess their capabilities before starting business. Having said that, I might ask them for samples for various purposes - or cut up a couple of the boards received myself to analyse the quality of the process.
n most instances, especially if you don't have the tools, the board house will cut and provide prepared samples to you, with, or without their own data. There could be a small fee, but for those initial orders, it is worth it to gain the confidence.