I'd say yes and no.
I've always consided a BOB something you evacuate with (i.e. Bug out) weather it be evacuate yout home or work. Now this BOB have enought supplies to survive 72 hours therefore it can be considered a 72 hour kit also.
Some don't beleive in bugging out, maybe they work close to home, or work form their home and they believe they have stocked their home well enough to stay if some situation happens. They may have a 72 hour kit but it may not be a BOB.
Then there are trucks kits, these can be a bob or 72 hour kit or both ot more. I have a small bag in my truck that I consider a BOB (I haven't really decided on the length of time it could sustain me) but have variuos other gear in my truck such as tools and spare parts which I consider part of my truck kit.
Confused yet <img src="/images/graemlins/smile.gif" alt="" />