I have popped my needles off of the speedo and gas. let me just say that this may nit have been the best idea (i was trying to keep my old odometer when i get a new cluster). The gas gauge came off and went back on okay, but i took it off a second time and it snapped the part of the needle that clicks in, so it sits in there now but does not work at all so i must count my miles on odometer as far as gas goes. Speedo came off easier and goes on easier... but i spent weeks trying to calibrate my needle to tell the right speed, since the little rod the needle sits on is uncontrollable when you pop the needle off. Now my speedo seems pretty accurate around 40-50 MPH since i drove by speed radars making it say that and popped the needle back on the display @ 40 when i passed the radar. I had to drive with the whole cluster open, probably not safe or a good idea either.
If you are very slow and careful it is probably doable right. The main issue is getting the gauges to read right after (i have 1997 dx, other models may be different).
I would say you are probably better off taking out the cluster and taping it off really well then just painting the needles while on the cluster.