Not necessarily,there's no hard and fast rules regarding classification amazingly,it could be simply down to the assessor on the day and the circumstances regarding the crash,as stated above could be someone was run down and killed in suspicious circumstances etc.

Charlotte church had her merc ml attacked by mice on her farm,all the wirings wrecked and it's ended up in a well known breakers in Swansea,that's cat b but aside from a bit of wiring and a new interior it's mint.

Particularly between cat c/d it's laughable,I've seen cat c's with literally a scratch down the side and your thinking "uh???" then I've seen cat d's that look like they've been dropped out of an aeroplane!!!