I have had these stamps for longer than I can remember. I do not see these listed in Scott. On ebay I see this listing that says
"BRAZIL-1927-AIRMAIL-CONDOR-SYNDICATE-set-1st-print-Sc-1CL1-1CL7-mint-MNH"
In addition to what Michael wrote: this may very well be the unissued second printing of the first Condor series. Prepared in 1930, never officially issued and consequently dumped on the philatelic market. According to Michel and RHM its c.v. is half of that of the first issue from 1927.
Main difference: brighter colours. But in order to really be able to judge that you need to have exampes of both printings :-)
