Welcome Newbie, There is a good tech Menu, Top bar, and use the search function, below your handle in the top bar. Not much you can't find in those two features.
2F0-204183 will make your bike an 80SG...........This was the first year of a lot of changes to the visual aspect of the specials, it also was the first year the factory ditched the points ignition for an Electronic ignition. It is referred to the as a, TCI Ignition, and has the advance built into the back box situated on the bottom of the battery box...........Carbs changed to BS34's........up until the 80SG, all models (70-79), had BS38's.........Under the cam covers, (chrome covers above the spark plugs), is where all models from 70-79 had their points situated..........In 80 Yamaha removed the points plate and associated parts, that went through the center of the cam. On your bike there shouldn't be any thing behind those covers...........If by chance there is something under there then the factory ignition, TCI, has been replaced with an aftermarket one..........if so then take some pics so we can identify it for you............
On that not take a few pics so the whole bike can be seen and we will look it over and help identify what you have............... A lot of parts interchange, and as is often the case with the age of these bikes this has sometimes been done.............
Do not buy anything before asking on here first. Often there are simple remedies to fix issues and id parts are needed then you will be pointed in the best direction or supplier to get things needed.