I wouldn't say it is necessary, but as cheap as pads are, unless the set is close to new, it would just be better to replace them while they are exposed.
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"Ignore that whistle, it's just a vacuum leak."
2000 Mustang GT:
Saleen Series IV Twin Screw, Chicane I/C, AFCO Extreme H/E, 2.8" pulley, FMS 42# injectors, Dual Catted 2 1/2" UPR X Pipe, UPR LCAs/UCAs, 2 1/2" Flowmaster American Thunder kit, 90mm LMAF, 112" Goodyear Gatorback, Kenne Bell BAP, Mosaleen idler, T-56, Detroit TrueTrac w/ 373s, Demolet 100mm CAI, SCT XCal2 with JDM Engineering 93 Octane "Race" tune.