Not necessarily.

Gupta is a surname used by people from different communities, including Jains, Hindus, and others. So a person with the Gupta surname may be Jain, but not always.

In Jain families, many surnames are based on gotra, clan, profession, or region, and the same surname can be found across different communities. So surname alone does not confirm Jain identity.

If you want, I can also explain which surnames are commonly found among Jains.