Yes I know that
That's why I stated earlier it wasn't hard in itself to replace the meshes. However it would still be tedious even with the Search & Replace function, there's the various hallway and room meshes plus pillars, altars and ash pits just to name a few.
Once again, it could be done just time-consuming and a little tedious. One could set a goal for themselves if they had little patience or get burned out easily; do tombs A-E for example then take a break and then move on to tombs F-N and so on an so forth. One would also have to account for the interiors that aren't tombs but contain the "Velothi" tileset, excluding Vivec, Vos and temple interiors.