Dart w/ 727 and Vibes and Yoke Question

It should have a boot on the seal

View attachment 1715599936
Does that enter into the equation, the extra boot length? Looking at the shaft there is a wear area that maybe lines up with the boot you show! Sooooo, in this scenario insert to the boot until flush and pullout 1" and go from there? That still leaves a lot of shaft unsupported, causing some real harmonics. Maybe the tranny shop did not replace?