Bob, you didn't post a pic or link...and because of that, several here may have blown off this thread...
(I'm going to try to get appointed Ed Tinker's 'hatchet man' and really get serious about pic posting here) 
In any event, can you tell me if an 'early' breechblock means one with a flat top, as opposed to the curved tops seen on P-08's???
What else differentiates an 'early' breechblock???
thankyouverymuch!!! 
Edit: I lucked out...Found them on the first try...(Not everyone calls this item a 'breechblock')...
drbecker (a name I recognize as a seller of Luger parts) has it...and they do have the flat tops...and use a different extractor (drbecker says)...
http://www.gunbroker.com/Auction/Vie...Item=227821252
I guess the next question is...can this breechblock (with its extractor & spring) be used on a later Luger???