There is no rehanama that says not to wear a Red Dastar. The rehatnama
says not to wear red dastar; instead, the Hukum is to not wear the red color.
ਸੂਹਾ ਪਹਿਨ ਲਏ ਨਸਵਾਰ। ਗੋਬਿੰਦ ਸਿੰਘ ਜਮ ਕਰੈ ਖੁਆਰ ।
Bhai Nand Singh Ji rehatnama
Guru Sahib tells us what the KHalsa colors are dark blue, white , and yellow
੧ ਸੁਰਮਈ ੨ ਸਵਯੇ ੩. ਪੀਤ ੪ ਹਰਤ ਬਸਤ੍ਰ ਧਾਰੇ ।ਬਸਤ੍ਰ ਕਸੁੰਭੇ ਕੋ ਨ ਪਹਿਰਹਿ
Bhai Daya SIngh Jis rehatnama
These are the traditional colors of Khalsa that many traditional Singhs like to wear.
Black and orange has also become a traditional color. Nobody is saying if you
dont stick to these colors you are not a proper Gursikh. These are just the traditional
colors Khalsa wore to remain distinct outwardly from others. Traditionally, the colors red and green were
not worn as they were associated with other faiths.
ਸਤਿਗੁਰਬਚਨਕਮਾਵਣੇਸਚਾਏਹੁਵੀਚਾਰੁ॥