I really need all four knobs for a Canadian-built Stromberg-Carlson Model 694 table radio. Somewhere along the way, somebody replaced them with four knobs which appear to be off Heathkit test equipment, so I have only a few clues as to what they look like. The radio still has all seven of it’s pushbuttons (thank God) and they are a dark burgundy colored marbleized plastic. I suspect the knobs also were similarly-colored plastic. The control shafts are the standard quarter-round ("D" shaped). I have looked at pictures of U.S. Strombergs from the same era (1946-47) and the knobs on those appear to be simple plastic jobs with a concave (dished) face. Any help you could provide would be greatly appreciated. Thank you.