Yours are a very early pair. The first two hundred had a significantly different crossover than later revisions while the first 999 had the CTS woofer. In the pictures you posted, the woofer looks to be a fairly recent replacement, possibly with a polypropylene cone. It's not the right one. Yours should have the original CTS that looks like this:?/g/DahlquistSpeakers/wiki/29012
Mirror-imaging DQ-10s was offered by dealers on an independent basis, but not something Dahlquist experimented with internally until 1976 and wasn't a factory option (in factory, at the dealer or via mail order kit) until 1977 after serial number 29093. The yellow polyester caps were introduced after serial number 22000 and were also available as a kit. So, those aren't original in yours and were likely changed after the fact. This can be seen in how the one crossover board has been flipped around to be upside down due to the wires not being long enough for the move from its original mounting position.
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The midrange dome looks to be a LPG, which are no longer available. They're good drivers and actually pretty sought after since they were used in some real high end speakers making replacements used or otherwise desirable for those models. That, unfortunately, also means getting a match to the newer driver very difficult. You'd have an easier time matching the extant Mikrofonbau MTL-37 (didn't become Peerless until MB was bought out in 1975) and reverting them to original. That'd be easy to find. The CTS woofers, though, those are difficult. The one set of originals I was able to get the photos on didn't have any markings other than the EIA code for CTS, so it's not known which replacement would work. Opting for the Gefco manufactured Advent-style replacements would be one option, but that would require redoing the crossover and, much more involved, cutting into the cabinet to make it so the larger 12" basket of those will fit.
