hifi engine

Unknown Marantz meter

I have a Marantz meter, large size, looking quite like a Model 510 meter, but has "bronze" or "gold" tint face with numbers as follows: on top 4140029AA, range of -20db to +3 db, 3" accross face of case, 2 1/4 " top to bottom of case, approx. 2" deep overall,
Dixon, Inc on case between terminal posts, and 2 terminal posts at top of rear on case.
What is it from??? Thanks very much.