Dial Bore Indicator vs Ring Gap Measurement , Small Engine

Briggs Cast Iron Engine, Is it a waste of money or not buying a Dial Bore Indicator. I tear this 16hp cast iron Briggs and Stratton cast iron engine down to see if the cylinder is ok to install rings. Using a Micrometer and a Dial Bore Indicator You can tell if the cylinder is worn out. Check for taper and out of roundness. If you do not measure you may buy parts that will not do you any good. You cam measure Ring Gap , but that will not tell you if your cylinder is out of round like a Dial Bore Indicator. Is my engine cylinder worn. Small engine repair, wtbm123. If you buy a piston and rings that are wrong , it can cost as much as a dial bore indicator.