Can I get the income deduction if I acquire KOSDAQ venture fund beneficiary certificates from someone else?

No. The proviso to Article 16(1) of the Restriction of Special Taxation Act states that the income deduction does not apply to investments made by acquiring another person's capital contribution, investment stake or beneficiary certificates.

In other words, only money you invest by subscribing to the fund yourself is eligible, and beneficiary certificates taken over from another investor are excluded.