It is very probable that the answering entity was a GMP -- but knock yourself out, if you want to be really sure it's a non-buggy GMP too.
I, for one, would find it rather cool if we had a thorough-test-suite that would attacks the random function too, subjecting its randomness to scrutiny, estimating the amount of entropy we get out of it and the like, but I doubt anyone in this community would go to the effort to craft it.