? about bag's and a-arm's

[Slammed '87]

I need new a-arm's for my '87 before i bag it. Are a-arm's interchangeable through '73 - '87, and where would be the best place to buy a new pair, keep in mind i am in Canada! I was planning on having my bag system professionally installed, but is it fairly easy to do yourself?, i do have have access to a shop etc. etc. Do front bag's just bolt in, or do you need to modify anything first? When you buy bag's do they come with all the nessesary hardware, or do u gotta buy it separately? Any and all info would be cool as i have never done this before! Thanks, Dean