Hello Patrick
No, the internal interface in this instance is not the same thing as an SVI. The internal interface is simply a logical construct used within the context of IGMP snooping to describe how the CPU learns about MAC addresses and the interfaces to which they correspond so that it can populate the MAC address table or CAM table.
An SVI, on the other hand, if it exists in an IGMP snooping scenario, will behave much the same as the physical interfaces of the switch shown in the lesson. It may also participate as the IGMP snooping querier, that is, the Layer 3 interface found on that particular network segment, just like the R1 router.
For more about the SVI interface, take a look at this NetworkLessons Note.
I hope this has been helpful!
Laz