This may be stating the obvious but one distinction you will need to make is whether you have head-light washers or not. A front bumper with washer obviously will need munting holes and vice versa.
The way I understand it is that the 997.1 range have identical shells except 4WD models, your 4S has wider rear arches. All other differences beween the models are differences bought as packages or extras by the first owner, including the 'S' upgrade which is just a bunch of modular performace improvement enhancement add ons as opposed to a body styling or aero-kits. The base car's shells are identical except the 4/4S rear end widths (to accommodate 4wd transaxle??.)
On that basis, I believe the front bumber will be the same for all standard (Non Aero, RS, GT, Turbo..) models. I.e. 997.1(C2/C2S/C4/C4S) and Targa ...
Just make sure that the donor car is a 997.1 model and NOT 997.2
Ps. Having owned my 997.1 for over two years, I have done a lot of fact finding about my car and I have had my front bumper changed, during my search for a replacement bumper I did not come across the distinction you refer to. And I visited many potential genuine part sources.
yours,
owner/driver and not an expert in the field.
