[avmich]

No, engines weren't ablatively cooled.

N1 had engines with quite high Isp - the problem for them, NK-15 engines, was that they were single use engines and couldn't be tested beforehand on a stand. They, however, were state of the art, high pressure and regenerative cooling, with oxygen rich staged combustion. However, Nikolai Kuznetsov had relatively little experience with rocket engines, so NK-15 is generally regarded as a failure, and NK-33 didn't have a chance to fly on N1 before the project was closed.