I agree, I wasn't trying to imply that they're in the rare category of the 10s', just that they are rare. Any PC marked mag commands a higher price. 4040PD mags were scarce, now it seems they've been becoming available. 39 series single stackers seem to be in demand lately.
Back in February when gunshows were still occurring, the big magazine/clip vendor at the Berea Ohio show was hurting for 59 series 14/15 rounders in S&W or aftermarket. People were buying because of the upcoming pandemic. 10 rounders for the 69 series have become difficult to find.