If you're handy and the opening is standard, swapping a door isn't impossible to DIY - but on housing stock from this era, the framing rarely is standard, and that's exactly where a first-time installer gets stuck. Getting the track plumb against a jamb that's shifted slightly over eight decades takes more than following the instruction sheet, and a door that's out of plumb by even a little will bind or drift within weeks.
Spring tensioning is the part we'd tell you not to touch regardless of the house's age - a torsion spring under load can cause real injury, and that's true everywhere, not just here. If you want to handle the trim, paint, or opener wiring yourself and let a crew handle the door, track, and springs, that split works fine and we're glad to talk through where the line falls on your specific opening.