Does a lump caused by a bone spur need to be removed?

Usually. A lump that is caused by an underlying bone spur should be removed if symptomatic. At the same time, the spur needs to be removed as well or a recurrence of the lump is likely.
No. Bone spurs form for a variety of reasons all other the body and occur most often near joints, although that isn't always the case. If it causes pain or redness or deformity it may be removed, but remember you will trade a bump for a scar which will be sensitive for weeks to months to years so if it isn't causing a problem don't fix it. If it is a problem you can expect some time before healing.