You won't feel timing chain slop in the distributor because you'd have to move the cam & valvetrain to do so.
The correct way to do it is to pull the distributor and check end play with a feel gauge between the gear & body. Turn by hand feeling for hard spots. Feel for excessive side play on the shaft.
Replace the distributor gear, some guys won't reinstall old ones on new motors. Others have no idea they're available seperately. Kits with hardened shims are available to tighten endplay.