Nice combo! It's a 1959 WD860S, and more than likely an S2 as the parts catalog skips over S1 and goes right into S2. It also should have lighted dials and is the first year for the variable drive belt for spin, vs. a dedicated two speed transmission found on the 1955-1958 models.
The 861 was the 115/208v version, with both being the only year for the fabric softener only dispenser. By 1960 GE brought over combo bleach and fabric softener dispenser and went with dark tones on the control panel, w/ lighted dials.
Ben