[aotte1]

Just a little summary, not trying to be .......
On non factory A/C trucks cross braces are riveted to core support top and bottom, as stated above.
On factory installed A/C trucks, cross braces are riveted on bottom and bolted on the top.
As stated above, when the dealer installed the A/C unit, the factory rivets where removed and bolts with spacers where put back, as shown in figure 1 above.
Also the cross braces on factory installed A/C trucks where different design, along with other core support differences.
Photos show the cross brace on factory installed A/C trucks.

Also, for me I would keep the cross braces, protects the radiator and core support from stress, stiffens the whole front clip.

Les