Actually, you may or may not need a calibration. If the screen material is made by the same manufacturer, they may be able (or willing) to tell you if the new screen has a different color balance than your previous screen. If the screens are made by 2 different companies, probably the only way you'll be able to tell if the screen is different than the old one is via measurements.
Changing the lamp also does not automatically mean you need a new calibration. It probably means you need a new calibration, but you wont know for sure until measurements are done.
So the problem is... you probably need a calibration, but you can't know for sure until some measurements have been done. if the measurements look good... no calibration. if the measurements are "off" from where they should be, you need a calibration.
There's no way for you to answer the question without those initial measurements though. So you can learn how to do measurements yourself (and purchase a reasonably good meter and acquire software also), or hire a professional calibrator.