I would say you need to be just aware of it and to know some changes in sh mpls forwarding IF the IOS images used in the lab are 12.4(20)T or newer.
There was another thread about this and some changes in the action associated to VPN labels had been described by Cisco Expert Harold Ritter.
From a configuration and troubleshooting point of view this change should have limited impact as described in that thread.
MFI may have the potential for new features however "conventional" MPLS should be enough for CCIE routing and switching lab also in CCIE R&S ver.4 because the CCIE service provider lab is really focused on MPLS.
see Ask the Expert with Maurilio Gorito about CCIE v4
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