SAM Radar SACLOS missiles

A lot if not all SPAA with radar guided missiles can be jammed by IRCM found on a few tanks. I was wondering if this is realistic or not

Many of them use IR flares at the back of the missile to locate it. Inorder to be IRCM immune, they would have to be coded, tbh i doubt you will find anything about it.
And many SPAA sould be immune to it while in radar mode, for example Rolands (excluding the french one), Crotale NG as in Radar mode, they are using radar to track the missle.