On the one hand, M/G tell us that corpses were found at Treblinka I:
On August 22 and 23, , the investigatory committee, accompanied by local Polish officials, went to Treblinka in order to carry out investigations on the spot. Three mass graves and 13 individual graves were discovered by this.The key point to note is that these bodies had not been cremated. With regard to Treblinka II, however, the Polish investigation of Łukaszkiewicz found that "nearly all of the bodies of the victims were burned." Mattogno and Graf conclude from Łukaszkiewicz's report that "the human remains as well as the ashes prove only that bodies were buried or cremated in the camp." However, not only do M/G grossly under-represent the volume of victims that Łukaszkiewicz's findings indicate (as Roberto showed here), but they also ignore the obvious question raised by the contrast between the two camps: why burn corpses at one camp but leave them in-tact at the other?
The only plausible conclusions are that the camps had different purposes and the Nazis needed to conceal the purpose of the second camp by burning as many of the victims as possible.