Dual spurs and dual mufflers aren't all that uncommon. It was just a matter of someone ordering a set made like that. The catalog sets were starting points and not set in stone. If you were willing to wait they'd build it the way you wanted it (or maybe the way a dealer preferred to have his stock sets made up). Some of the bigger drum shops ordered drums with no mounting hardware so they could install whatever a customer wanted (say a Rogers tom mount on a Ludwig set).
It seems many folks are very concerned with what the "catalog police" will think when a set has these sorts of aberrations but the drums all sound the same whether they match the catalog picture or not. I do realize that due to these perceptions "catalog" sets tend to sell for more money than those with some minor (and likely factory installed) change in detail...but these are still valid sets.
