fuel pressure regulator replacement

Hello!! Just replaced the FPR in my 2000 Bonneville (3.8L w/o supercharger). The old one came out with two O-rings, a strainer/screen assembly and a spacer between the strainer and the larger O-ring. The replacement included all parts except the spacer. Tried reassembly with the old spacer and could not compress the assembly enough to get the snap ring installed. Installed all the new parts without the spacer and the car ran like a champ. I've checked, and there are no leaks, either through the diaphragm (my original problem), or from the housing in the fuel rail. All the severe problems I had before are gone. My question is this. Is the spacer critical, or can I get along without it? If it's necessary to maintain alignment and seating of the strainer or O-ring, can it be shaved to make installation possible? I'm hoping that since it was not provided in the replacement kit, maybe it was just for original assembly. If is is critical, does anyone know any tricks for getting this thing back together? Thanks for a great forum and thanks in advance for any help.