I believe that if you are lucky enough to get a good delivery team that WANTS to get it in the door, they will be able to do so, either sofa or sectional. People are people and some work harder than others. If the delivery guys show up and say 'That ain't goin' in there', then that - as they say - is that. But if you get a good team that knows their craft, they should be able to do it.

Here's a suggestion - you hand each of those guys a bottle of cold water when they arrive and say "Might be a tough delivery - if you can get it in my place I'll have a tip for you both and we won't worry about any little rub marks." And also have a # 2 Square Drive screwdriver on hand in case the legs have to come off as they won't have one of those on their truck. That will make a difference in the event things are tight.