Post process colour matching is probably the only option, besides eye balling it. You have to keep in mind that your material colour is influenced by several factors (and that RGB is a screen colour not a reallife one). Releftions, shadows, sun temprature, HDRI/Sky, etc. So even if the base colour is perfect your render should look different when all these factors have influenced it. On top of that if a material has a texture (it does) with a base colour (probably), the RGB you enter in TM is just an overlay on the base textures colour, so your end result isn’t the RGB code you want.