Book by Victor Markovsky mentions VP-50 installations on ML, MLA, MLD and even UB going to Afghanistan. Unfortunately all clear photos that I've found are MLD's. But multiple MiG-23ML pilots and technicians on many forums and Razbam discord stated that VP-50-60 launcher rack is bolt-on. MiG-29 flare dispensers are also separate bolt-on device and not part of the airframe btw.
UPD - there are photos of UB with VP-50, which is technically an MF with dual cockpit. So if can mount it on UB which is like really different from MLD, mounting to ML should be no problem at all.