Yes, you can just copy the folder like you've described.
When you import it in your application, you just use your new import path:
import (
"github.com/user/parse"
"github.com/user/template"
)
It is completely safe to do that. Just Go ahead and code!
Ps.
I assumed your path would actually be:
$GOPATH/src/github.com/user/parse
since the domain (.com) will also be included in the go get
path if you use github to host your package.
Ps2.
Remember to update the imports in the github.com/user/template
package to refer to your new parse
package instead of the original one.