[GMCNUT]

I've seen the clock and tach installed both ways - I found a 1 owner 41,000 mile untouched 62 or 63 GMC once and it had the tach and clock put in from the front, and the original owner told the dealer he did not like the "new" all black plastic knobs vs the nicer chromed steel ones from 59 back, so the dealer removed all the black knobs and replaced them with 55-59 chrome ones - I have to admit - it looked better. So point is, when something is dealer installed, the "correctness" of that installation was subject to who was doing it, what they felt like doing that day, and what dealership they worked for. Generally speaking I believe rear mounted is what we should all consider to be "correct" but like Greg said - when the clock is mounted this way you cannot adjust it as easy as you can if front mounted. That could be one reason to mount from the front