Can I update to OS X 10.8 from OS X 10.7 without doing all softwares updates?

Do I have to perform all system updates to Lion before I update to Mountain Lion?

Yes, I was able to update from 10.7.3 to 10.8 without running software updates (10.7.4) and Mountain Lion runs great.

Yes since you are running 10.7.x you can update straight to Mountain Lion and not have to update to the latest version of OS X Lion first. This capability to jump from any version of Lion to Mountain Lion is noted in how to upgrade to Mountain Lion.

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Step 2: Make sure you have Lion or the latest version of Snow Leopard ...

If you are running Lion (10.7.x), you’re ready to update to Mountain Lion. Go to Step 3. If you are running Snow Leopard (10.6.x), update to the latest version of OS X Snow Leopard before you purchase OS X Mountain Lion from the Mac App Store. Click the Apple icon and choose Software Update to install Snow Leopard v10.6.8, the latest version.

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