That's not primer in the engine bay if that's what you meant. It's un-lacquered top coat.
You'll do very well to find a second-hand front panel that has no corrosion. They take quite a lot of abuse. A new one is prohibitively expensive.
The front panel is held on with a number of small spot welds on the end flange of the chassis rails. You will need to drill these out. It's not as bad as it sounds and the replacement panel doesn't need to be spot welded back.
It's not the quickest of jobs replacing a front panel. There's quite a lot of dismantling to do - bumper/bar/shock absorbers, air ducting, headlamps, bonnet catch/release system, headlamps, power steering cooler pipe, wiring loom clips, under engine tray, air con rad if you have one. Neither the main rad or air con rad need removing though. Just prop up as you work around. You will also need a selection of replacement fixings like the plastic rivets used to secure the air ducting and the wiring loom clips. You may be able to reuse them but I routinely replace them. You may well find the bonnet release system the biggest challenge - take a look on the Pelican web site for a How To. Make sure you have a good quality 8mm metal drill bit to take the spot welds out. You could use a 10mm bit but I feel that would take out too much metal. I just gave a gental tap on mine with a large bolster chiesel between the surfaces to break the remaining weld away and I think I had more metal left as a result.
You haven't got a Topaz Blue one tucked away there too have you Brian?