hello i inherited a handful of old knives that were my grandad's. all but one of them are schrades. i grew up loving the 30t cause thats all i ever saw. anyways one of the knives is one of those linerlock trappers and it has no tangstamp of any kind. Was this common?, or did this one just slip through the QA guy or gal? it is an american old timer although it doesn't say it it it was purchased way before the closure as my grandad passed in 1999 i was just curious if anyone else has an unmarked knife? thanks allot