Not really, MiG-21bis is completely different beast to MiG-21PF/PFM used in Vietnam.
Vietnamese used PF/PFM. Only 1 hardpoint on the wing instead of 2. Only R-3S (technically could have R-3R aswell but NVAF never supplied with it to my knowledge) and PF had no gun at all, PFM could mount a 23mm gunpod on the fuselage hardpoint, along with much weaker engine.
MiG-21bis however is appropriate to use as Egyptian or Syrian MiG-21MF during Yom Kippur War. Only use R-3S as A-A weapon, anything except Grom or Nukes as A-G weapons and never touch emergency afterburner.
And MiG-21bis itself was used in Iran-Iraq War alongside MiG-21MF, interestingly, Iraqis managed to rig R550 Magic missiles to their MiG-21 and increased its power over the frankly disappointing Atoll missiles.
Both of situations were against F-4 Phantoms (among other types)