it may not be hardened but it could very well be tempered. just cause ya can cut something with a file doesnt mean it isnt heat treated at all, if it were very hard then ya wouldnt be able to cut it with a file, but many parts like drawbars are heat treated and tempered to be made "tougher". for example, a truck axleshaft can be cut with a file, not as easily as mild steel but it can be filed, yet a truck axleshaft is most ceartainly heat treated. so i wouldnt be so ceartain that it isnt heat treated, the drawbar on my ford 8000 can be cut with a file, but i know it is heat treated since it holds up to alot more weight than a bar of mild steel that size would. the aftermarket drawbar on my fathers ford NAA doesnt apear to be heat treated tho, as ithas been bent a few times, it is almost the same physical size as the one on my 8000, just its probably not heat treated. but some small compacts may just have a mild steel drawbar since they cant pull much realy. so i dont know wether or not your drawbar is hardened, i am just saying that the file test just tells ya if its real hard, not if its heat treated to some degree
