That's a thorough inspection for sure. Interesting that Van's doesn't specify it in the RV-12 Maintenance Manual.
Van's doesn't document inspections and procedures for parts and equipment produced by others under a specific ASTM (there are separate ASTM's for engines, propellers, etc.). At least not any more, for the reasons mentioned below.
Those manufacturers are responsible (mandated by the ASTM that applies to their product) for their own maint. and inspection procedures, and the documentation for them.
Another reason Van's doesn't do it is because every time a manufacturer makes a revision change to their procedures or processes, Van's documentation would have to be updated as well. Keeping track of all of that would be very burdensome.
When the RV-12 was introduced and the Sensenich propeller was still very new on the market, the documentation was much lower in detail than it is now.
I could be remembering wrong, but I don't think it originally specified that the propeller be disassembled for inspection.
Interestingly... one of the marketed benefits of the 3 blade prop. is that it can be removed from the engine as a complete assembly, without disturbing the pitch setting of the blades. I don't know whether complete disassembly for inspection is prescribed for that version.