The awnser to your question is yes. However you may wish to wait a couple of months to see how things work for you with the new version.
There are lots of changes from version 2 to version 4 and its advisable to view some of the free tutorials on the Adobe web site which explain the new features. Better than running into problems as lots of users have done by converting all their files from the older process version to the new process.
I would emphasise the advice above. I installed v4 and it correctly created a new catalogue from the 3.5 version. Then I found I had lots of problems with version 4 (not everyone seems to be so afflicted). For me LR4 is on hold, until the problems are fixed, and I'm using 3.5 happily wit its own catalogue. I strobgly advise you to wait until you are completely happy with version 4 before dropping the earlier one. I'm sure it will be fixed in time but at the moment it dosen't work well enough for me.
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