Interestingly, under the heading George VI (1936 - 52), in relation to mint darkened coins, Freeman says this:-
"Some pennies of other years also appear to have been treated with 'hypo' unofficially"
ETA: With regard to 1944 undarkened, I found this - no idea how experienced or knowledgeable the guy is, but he sounds as though he knows his onions.
Of course, the last paragraph takes me back to my thread on mint darkened 1935 pennies (or the possibility thereof).