GL1100, identify correctly

hi all, please tell me how i identify my bike properly, its a gl1100 interstate and has 1982 on the headstock, is there anything more i need to know? i need sparkplug caps and it seems they vary from year to year. also i posted on here a week ago about regarding a sooty black plug, i ended up removing the carbs, you should have seen the crap in the float chambers/jets etc im surprised it ran as well as it did! thanks and regards chris