If you've replaced a heater core, I could use some help / advice.

My Jeep Repair manual says in the heater core removal process to...
"Cut the retaining strap that holds the blower/evaporator housing to the heater core housing"

The re-installation instructions say to...
a) Secure the heater core into the housing with the screws.
b) Be sure to cement the seal in place to keep it from moving when
the blower assembly is installed.
c) Re-install the remaining parts in the reverse order of removal.

Question:
I haven't been under the dash yet to see, but does that mean I need a new retaining strap to re-install the core?
Or does the "cement" mentioned in b) act in place of the retaining strap?
Or is there some other way this gets done?