My FSDO says the factory dataplate is fireproof, and suffices for that requirement. The one that they want outside, on the aft tailcone near the left horizontal stab can be written with a sharpie on a piece of masking tape, so long as it's legible. P-touch labels, plastic embossed labels, or even a piece of white paper held on with clear tape would suffice.
Absolutely correct.
14 CFR 45.11(a) and (a1) specify the fireproof plate requirement, but (e) says:
"The owner or operator of an aircraft manufactured before March 7, 1988 must mark the aircraft by attaching the identification plate required by paragraph (a) of this section. The plate must be secured at an accessible exterior or interior location near an entrance, if the model designation and builder's serial number are also displayed on the exterior of the aircraft fuselage. The model designation and builder's serial number must be—
(1) Legible to a person on the ground,
(2) Located either adjacent to and aft of the rear-most entrance door or on the fuselage near the tail surfaces, and
(3) Displayed in such a manner that they are not likely to be defaced or removed during normal service. "
Note that nothing requires the external "display" be fireproof, only the placard at the "accessible" location.