[rsk289]

My opinion would be that both instruments are replacements.

COB cars, to the best of my knowledge, had instruments with cylindrical black pointer bosses. The chrome pointer boss on the tacho here looks like the instrument's from a different model - maybe MG, etc. The photo isn't clear, but I can't make out the scalloped section with the red high beam indicator lens in it either. Similarly the speedo dial doesn't look like any I have seen in a COB car, both in range and in the existence of the inner KPH scale. likewise the pointer boss appears flat rather than drum-shaped - modern repros have this flat style of satin-black boss. Clarification of part numbers should help enlighten...
The ammeter's a later part, too, but I can't make out the other instruments.