There is no specific UCMJ Article concerned with the wear of the military uniform. If a service member is charged with improper wear of the uniform, it is likely to be a "Failure to follow direct orders" sort of situation.
Each branch of the Armed Forces has its own uniform regulations. Each of these lay out recourse for violation of the reg. See below:
See each of the applicable for specifics.
What article of the UCMJ covers fraternization
Article 134
Article 134
Article 92
Article 86
Article 134
Article 92
134
134
It defines who is subject to the Uniform Code of Military Justice (UCMJ)
108
86