You can peak into the oil fill hole with a flashlight and see if there's any obvious sludge. My guess is that it will be clean. The P.O. probably used good oil at first anyway, and I don't even know if they sell anything these days that will sludge up a modern engine.
Around 1990 I had an '80 Ford truck with a 302. The thing had so much sludge built up that the rocker arms had carved out an area where they travel and the rest of the valve cover was packed solid!!!
Paul C's suggestion to change the filter in the middle of the first round is a good one.
Experience is something you don't get until just after you need it.