No, they are two different Upanishads.
- MuNdaka (Sanskrit: मुण्डक) literally means "shaved (as in shaved head), shorn, lopped trunk of a tree". It seems to imply the message of a self-realised monk establised at the highest state of realisation.
The root of MANdukya is sometimes considered as Manduka (Sanskrit: मण्डूक) which literally has several meanings. It means "frog", "a particular breed of horse", "the sole of horse's hoof", or "a kind of coitus".Some writers have suggested the "frog" as the etymological root for Mandukya Upanishad.
Another root for the Upanishad's name is MANduka (Sanskrit: माण्डूक) which literally is "a Vedic school" or means "a teacher.
- The MuNdaka Upanishad opens with declaring Brahma as the first of gods, the creator of the universe, and the knowledge of BrahmaN (Ultimate Reality, Eternal Principle, Cosmic Self) to be the foundation of all knowledge. The text then lists a succession of teachers who shared the knowledge of Brahman with the next generation.
The MaNdukya Upanishad is an important Upanishad presents several central doctrines of the AdvaitavAda, namely that "the universe is Brahman," "the self (soul, atman) exists and is Brahman," and "the four states of consciousness". The Mandukya Upanishad also presents several theories about the syllable OM, and that it symbolizes Self.
The MANdukya Upanishad is a prose containing only twelve verses. You have already mentioned about the MuNdaka-Upanishad.
Both are parts of the Atharva-Veda.
Source : 1. Upanishad-Granthavali, Swami Gambhirananda, Udvodhan, Vol. 1
- Wikipedia pages on the two Upanishads.