Just curious, were Otto Links metals and HR models more or less the same internally, or were they designed with different sound concepts in mind?
I don't remember the exact year that the rubber pieces diverged so much from metal, especially in terms of the baffle design, with the rubber pieces having that scooped out baffle (making them tubby and resistant), but I can remember buying a tenor Link piece in Sam Ash (NYC) around 1993 or so -- it may have been new-old-stock -- and it having a normal, not-scooped-out baffle. That is a huge difference between the metal and rubber recently, a more traditional rollover baffle, similar to but not the same as earlier STMs as far as the metal pieces, and the HR being so vastly different from both the STM and earlier HR in terms of the baffle (as Sigmund451 describes above).
I haven't ordered any stock Otto Link HR in years, since a few years after that change to the HR, because...honestly...there really hasn't been a reason to.
I would imagine the recent "lost wax" editions have gone back to a rollover baffle in the HR editions. I haven't bought any, so I don't know/remember anything from 1st hand experience with these because I have none.
It does appear they went somewhat back to the previous baffle design for the "vintage" HR line -- a quick Google-up hits NeffMusic.com, and the photo there makes me say that:
^ to OP: if you haven't seen that page, and it sounds like you haven't, it probably has a lot more info that you didn't ask, but want.