These dudes can answer ALL of your DQ-10 questions!
I did a google search for Dahlquist and found this info on a web page. lower mid looks like a Phillips AD5060
Also, give Simply Speakers a call or check out their web page. They rebuilt my woofers this past May for around $60 each. They also rebuilt my DQ 1W driver. I understand they can repair any driver in the DQ10. They are very good at what they do. They might also know what each driver make is.
As Rwwear stated, the woofers are Advents - the type with the masonite ring mounted over the metal basket. It is a very good woofer, reasonably long-throw (for it's era) with an oversize diameter foam surround.
If the foam surrounds are shot (which they must be) re-foam them - do not buy "replacement" drivers.