You have to specify what you mean.
If you mean the actual sound -- yes, it happens to have existed.
If you mean whether the sound existed in the history of Mandarin, not Middle Chinese -- yes, it happens to.
If you mean whether at some point the character 䄝 was pronounced like Modern Standard Mandarin
chiang, uh probably not.
To go through some Middle Chinese reconstruction details, 丑 has onset 徹 in MC, reconstructed as *[ʈʰ], and 江 belongs to the final group 江, reconstructed as *[ɰɑwŋ], and has the "Level" tone. So in (my version of) the MC reconstruction, 䄝 was pronounced something like *[ʈʰɰɑwŋ] in some stage of (early) MC.
Now, this syllable eventually became MSM
chuang1 through sound changes. But if you are wondering what happened to something close to *[tʂʰiɑŋ], the medial [-i-] became [-u-] in that particular position and became MSM
chuang as well.
You might wonder what the heck happened so that you get superficially in MSM
ch + iang = chuang in this case.
The onset 徹, reconstructed as a stop in Early MC, entirely became an affricate *[tʂʰ] at some point (and merged with the existing retroflex affricates). This is why you don't see this sound change superficially.
The final 江 developed differently depending on the conditions. In any case it was completely merged with the final set of 阳 *[ɑŋ]. The medial *[-ɰ-] disappeared in most cases, but turned into a [-u-] after retroflexes in Mandarin, and, distinctively, developed into an [-i-] after dorsals (i.e. velars, and glottals if your reconstruction has them) in historical Northern Mandarin dialects. Now, the character 江 happens to have a dorsal onset 见 *[k-] (velar), so the medial *[-ɰ-] there turned into [-i-], which, by the way is how you've got the palatalized onset