Prior to electrification, the area in question was "Two or More Tracks" with Rule 251 in effect. So yes, there were signals east of Divide and a Timetable specified Current-of-Traffic, much like the area between Babylon and Y, Nassau to Locust and Jay to Bliss.
Joe, on the Mainline in former Single track Rule 251 territory, the signal foundations you see east and west of the areas you discussed were for Distant signals that were lit when the location was open as a Block Station and the Block signals. Just like when you approach PD, MS and even when you travel west approaching KO2. The Mainline in those days commonly had part-time Block Stations..the Station pages would note when they were actual Block stations which were manned and controlled locally by the Agent-Operator with actual Block signals and Distant signals. Unmanned hours they were Block-Limits controlled by either B Tower or Divide.
The last regularly scheduled part-time Block stations were on the Pt. Jefferson Branch at Port Jefferson and Stony Brook. Like the Mainline, when they were unmanned, they were controlled by Divide and in the case of Stony Brook, it was a Block-Limit signal (BK).