Is it possible to find out the PacBio chemistry from the PacBio Sequel BAM's header? Is it possible to find out the PacBio chemistry from the PacBio Sequel BAM's header? E.g. whether it was produced with P5-C3 or P6-C4? I checked mine but I haven't found it but maybe it's hidden in one of the tags whose meaning I don't know yet, like SEQUENCINGKIT=100-861-800?
According to PacBio Sequel BAM format manual, you can find information on the chemistry version in the header entries @RG (read group), tag DS (description), entry BASECALLERVERSION . 

In case of future very PacBio-specific questions, you can contact Liz Tseng on Twitter (@magdoll), one of the most responsive PacBio developers. They also have a dedicated SeqAnswers forum, which is directly monitored by them and you are very likely to get a fast and accurate answer.