I really don't think so. I know that people have turned them into mini fuges for a SW setup, but I don't think that would benifit a FW setup. I really can't think of anything in the HOB that would be worth salvaging.
If you leave the HOB alone, it would give you a fall back filter system just in case the DIY canister doesn't work out. If you take it apart, and still have problems, you then don't have a backup. It may be worth it to just leave them alone until you are sure the canister works.... just clean them really well before putting them up.