The 1949 constitution is here. The wording has not changes in any material fashion that impinges on religion, and there is no specific mention of hijab or other items of apparel. However, it is not trivial to mention the provision in Art. 25(2)(b), which is still valid, that "The wearing and carrying of kirpans shall be deemed to be included in the profession of the Sikh religion". There is a legal principle to the effect that if you say one thing and don't say another, you can infer that it was not intended to include the other. Given an opportunity to also explicitly constitutionally include the hijab as a "profession of the Muslim religion", and the fact that it was not so included, the courts would concludes that there is a stark difference between the kirpan and the hijab.
There have been various tweaks to the wording of provisions related to religion since the original version, but none that would affect how the courts would interpret this case. The Karnataka ruling discusses the concept of "religion" versus "culture" (proffering the decidedly Hindu-centric view that "religion" is "dharma"), and they posit w.r.t. the hijab that "At the most the practice of wearing this apparel may have something to do with culture but certainly not with religion". In other words, the words of the constitution don't tell you what status the hijab has.
