I put it all in table form. The four columns on the right are all the recent issues of SCM that I have (per year of publication date) which I used to confirm this rotation.
|Publication Date||Cover Date||Checklist Contents||2015||2014||2013||2012|
|March||May||Baseball - BBM||104|
|May||July||Soccer - J League?||105||99|
|July||September||Baseball - nonBBM||106||100|
|September||November||Soccer - non J-League?||107||101||95|
I want to note here that SCM actually uses the English word "soccer" in labeling those two checklists which I find kind of surprising.
I have a couple issues from 10 years ago that do not follow this pattern so I don't know how long ago this particular sequence of vintage checklists started. And of course, past performance is no guarantee of future performance. But I'm pretty confident right now that SCM Issue 110 (which comes out Saturday) will have the complete BBM listing for its vintage price guide.