The speedometer will be off by a factor of 4. The 2010 chassis has a diamond drive, and the 2014 has a chaincase, and the number of pulses per rotation are different between the two.
That being said, once a gauge is reflashed it can be used on any sled that supports the deluxe analog style gauge. You can find out more about the reflash here: http://www.nextstagegauges.com/home
Do you know if a 2012 gauge would swap over without a reflash? I'll probably do a reflash in the future but for now just need to get it working. Thanks!