MPLS QoS quesiton

Hey Guys, wondering if you could assist.

We currently manage a customers CPE. This device is configured with MPLS (LDP speaker) but only on the WAN side of the connection. We are trying to apply QoS for VoIP and RDP. Looking at the following link:

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/qos_nbar/configuration/xe-3s/qos-nbar-xe-3s-book/nbar-protocl-discvry.html#GUID-2BA2DB07-F131-4FDD-BCF4-732EA87FDC51

We cannot use Nbar to match MPLS traffic as Nbar only matches IP traffic. The WAN interface of the router is configured with a shaper and a nested policy, so we can apply QoS. Traffic routes through this device as follows:

DATA --> IP (router) MPLS --> DATA

LAN traffic hitting the router is native IP. However, the router transmits this on the WAN side using MPLS. In the above link it says the following "You can, however, use NBAR to classify IP traffic before the traffic is handed over to MPLS.". Given this, should this QoS policy work? When I do "show policy-map interface" I can see traffic is being matched.