The OTR's are built in same area however if you mean CT putters they are built in a different building.

Custom putters are made at The Studio and OTRs at the main Titleist facility.

There are two different types of custom putters. One is the OTR that has custom specs like +1/2" or 1 degree flat lie which is done in the main factory, the other type of custom putter is called a CT or Circle T which are putters made for tour professionals or top amateurs and in some cases players willing to pay upwards of $2,500. These CT putters are made in the studio which is a different building than the main factory.

Hope the clarification helps...