Seeing as how this engine seems so far to be assembled correctly (no small deal!), check the ports real close to see if they've already been worked over.
One fairly quick/easy way to tell is to measure the port throat diameter right below the seat's last angle. See how close to 80% of the intake valve's diameter this area is (around 1.7" would be about 80%). That would indicate serious effort had been made, not just a brush w/a sanding roll to smooth things a little. This does require a valve be removed, obviously.
You can also look for evidence of the chamber being relieved to remove shrouding of the valve. Sometimes you will be able to see some scribing left from where the ports were gasket matched, as well as seeing how the gasket port opening compares to the head/intake port opening.