technically, yes. on virtually all the amps you are going to come across, this is the rule of thumb.
virtually ALL car amps are stable at 4ohms and higher.
two channel amps (class A\B) and more (4 channel, 6 channel ect - just no hybrids) are stable at 2ohm and higher (NOT BRIDGED), but can ONLY be bridged at FOUR omhs or higher. if you bridge the amp at 2ohms or lower, you have good chances of blowing that amp up.
mono - class D amps, are almost always 2ohm stable and higher - SOME (must list in specs) are 1 ohm stable, and even further, SOME are stable even lower than this. mostly competition amps and really oldschool amps that were built with very great components. mono amps (usually) only have ONE signal (rca) input. so they are only menat for subbass (whilst you CAN use them for music, its not recommended imo lol )
there are exceptions, there are special amps, theres all kinds of crap, but unless you know otherwise, never bridge a 2 or 4 channel amp below four ohms, never run a 2 or 4 channel amp under 2 ohms regular, never run a class D amp under 2ohms (unless it specifies it can handle 1ohm) and you will be happy for the rest of your life.
enjoy.