Parametric tests for bootstrapped means How can I compare two sets of bootstrap means, each with sample size $n = 500$? Can I apply a t-test?

The answer is yes, you can compare the bootstrap samples by means of a $t$-test. But, since the out-of-sample set is, I believe, the same for all models, you have paired data so the correct test would be the paired $t$-test or its non-parametric variants such as the Mann-Whitney test.
