Hi Arix,
Looking at the configuration, you will able to verify the kind of VPN. Also, in the command of "show security ipsec security-associations index <X> detail", if its a policy based VPN, you see the Policy-name but will not be seen in the route based.
In route based VPN, you use a tunel interface where you the direct the traffic to that has to take the VPN. You would see the st0 interface being used. This is not need in the policy based VPN. The traffic selectors are to be configured in this case which is not necessary in otherwise.
In policy based VPN, you refer the VPN in the policy thats configured for the traffic that has to take the VPN.
For more differences and detail, please refer to https://www.juniper.net/documentation/en_US/release-independent/nce/topics/concept/policy-based-route-based-vpn-comparing.html
And configuration in short and compare, https://www.tunnelsup.com/juniper-srx-configurations-for-route-based-and-policy-based-vpn/
Hope this helps.
Thanks,
Pradeep
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