You will need to get the parts list for each year and model of bike you are interested in. Either physical parts list book or find the PDF online.
HRC is not officially represented in the USA (I assume you are US based) so you cant do a walk-up parts counter search, but you can take the part number with you and try get a price.
But then you may as well stay home and search for it on PartZilla.
I have a large library of HRC parts lists and can try find the part # for you- what bike and what part you looking for?
The Good RS250R NF5 The Bad TZ250 2KM The Ugly LS7 C5Z07 Gone but not forgotten RC45 Delivered US SP2 #65