Black text in PDF's aren't overprinting in InDesign or Acrobat Pro

Hello! I started a new Design & PrePress job at a print shop. I'm new on the scene and been leaning heavily on forums for help but haven't been able to find a resolution to an occurring problem: black text on a PDF won't overprint!  Because it's a PDF I can't use InDesign's Attributes > Overprint fill. I've tried editing the PDF in Acrobat Pro and felt pretty clever by removing each layer and joining them in InDesign for the press but the black still leaves white behind. I have also tried using Acrobat Pro's Preflight settings and in PDF Analysis > List black objects set to overprint. I have successfully made plates without overprint by sending out the black first then building new color boxes and sending those out separately (if that makes any sense) but it seems like too many steps and leaves the door open for accidents. There has to be a better way!

This shouldn't be an issue with most designs but we use old offset presses and it's difficult for the pressman to register the black text over such a small white target... I don't want them to hate me! Any ideas or suggestions?

What I'm looking for is a flat orange color and the text prints over without knocking the orange out when separated. Here's what it looks like:

Thank you for taking the time to read this and reply, I can't tell each of you how much I appreciate all your help and the questions you ask... you all save me on a weekly basis!