John........the engine serial number is just AFT of the oilfilter, weakly hand stamped in smooth boss just under the cylinder head gasket seam. All you really need to know for maintenance is how many nipples the dizzy has. The weird 4-nipple frontmount squarecan 1-wire dizzy ...or... the common looking 5-nipple sidemount with roundcan coil. You can count nipples, can't you???
Ittza 2-bolt, 15-min job to remove the 4-nipple dizzy and replace the points (0.015") on the kitchen table. Gently stretch the squarecan coil spring so it makes certain contact with the points (0.015") screw. Just un-snapple yer capple and letter dangle. Installation is a reversal of the removal ...except... finger start the 2-bolts and install the rotor. Twist the rotor OFF-SET drive tang to fit into the camshaft OFF-SET drive slot. OFF-SET drive scheme means you never have to worry about re-timing. Now tighten yer 2-bolts and re-snapple yer capple. Simple, eh?
Remember to "polish" the INVISIBLE corrosion from between the points after installation. Me? I clamp a clean $1-bill between the points and pull. Iff'n yer really cheap, tear a strip from HEAVY brown paper grocery sack and use that. .........Dell, yer self-appointed sparkie-meister