MCT should still detect a gen1a as a mifare classic even if it cant write to it. The sak and atqa are off for a mifare classic too. I would say run this through taginfo to what its coming up as. Otherwise try and give it a format through tagwriter or nfc tools. I’m sure the usual suspects can come up with the necessary proxmark commands.
The atqa 0008 and sak 20 don’t match for a mifare classic. Haven’t seen that SAK before but according to this datasheet the SAK coding is for a Mifare Plus or Mifare Plus CL2. You didnt by any chance miskey the atqa instead of the sak using other software or proxmark?