Attacks on the RawCBC-MAC if the final step of encrypting with a second key isn't done
Is this also a valid attack on RawCBC [...]?

Yes. Writing down the expressions, we get $t=F(k,m)$ and $t'=F(k,w\oplus t)$ - while abusing notation and meaning RawCBCMAC for multi-block invocations of $F$. Now the actual tag for $(m\|w)$ would be $t''=F(k,F(k,m)\oplus w)=F(k,t\oplus w)$ which is equal to $t'$.