The housing accepts either male or female contacts, so it can serve as either the plug or the receptacle half depending on which terminal you load.
The closest functional peer in the same series is the 1-1376477-6, a 6-position plug housing at the same 0.098" (2.50 mm) pitch. Both are single-row, latch-lock, free-hanging housings that accept male or female crimp contacts. The 350779-4 gives you 4 positions; the 1-1376477-6 gives you 6. The choice is simply the circuit count your BOM requires — the pitch and contact system are identical, so the same terminal part number and mating housing family work for both.