Way too many trucks/bed lengths/and different versions of fifthwheels out there for there to be one conclusion/answer for this. Can most short bed trucks with most newer fifthwheel trailers be operated without a slider in most circumstances? Yes. Can all short bed trucks with all fifthwheel trailers be operated without a slider in all circumstances? No.
And the different sliders have different limitations. Manual sliders, once slid back can operate past 90 degrees. The superglide will slide itself back but can not be operated past 90 degrees. There are very few times when anybody should be operating past 90 degrees.