Am trying to determine Gruen's 5th ave. address for special case work duration and how they marked cases. Seemed to mostly do the platinum and diamond lady w.w. Saw a fine 18k man's w.w. case ..marked fifth Ave. I have Bulova 21j and 23j both USA marked. 21j gold fill case is marked same as the Gruen plus H3xxxxx number. Was that a Bulova USA address, not a case made for Bulova at the Gruen address by the contractor doing work for Gruen? The Bulova 21j is older than 23j I have photo of that is in Wadsworth 14k. Both 15x18mm.