There's no option in Redirect Map Manager to add the type of redirect. You can do that at Apache Level using Apache Rewrite Rules.
Ex:
RewriteRule ^(.*)$ ${map.legacy:$1|/} [L,R=301]
As per https://adobe-consulting-services.github.io/acs-aem-commons/features/redirect-map-manager/index.html, I see that Daniel has responded to your question.
Prateek, not directly in the Redirect Map Manger UI, but you can control this at the Apache level by how you configure the rewrite rule e.g.:
RewriteRule ^(.*)$ ${map.legacy:$1|/} [L,R=301]
vs
RewriteRule ^(.*)$ ${map.legacy:$1|/} [L,R=302]
To enable configuring both 301 and 302 redirects you could create two sets of redirect properties and configurations (each using a different property) and then configure each differently at the Apache level.