Yes. Easier to ask them. Honestly, I think the only way to legitimize the delegitimization of the caste system is for everyone to declare their castes. No shadow games. It’s all out in the open.
Heck, when I moved to New Delhi, everyone thought I was Sikh because my last name is Singh, even though my last name is a common Hindu last name in general and not specific to Sikhs. So not even Indians are guaranteed to have the mapping of last name <-> demographic correct.
(Speaking of, do all Sikhs count as Kshatriyas? Even the farmers in Punjab and Haryana? So confusing...)