I have tried numerous dealers in the San Diego area and none can get ahold of the 20" IC choke rifle-sight parkerized w/synthetic stock...none of their suppliers have them. Have you seen them advertised anywhere on the net?
Hmmm, nope nowhere on the net. I got mine from a local dealer who's son I grew up with, he special ordered it for me and I can't for the life of me remember which distributor he used.
Have you tried getting a Shotgun News or a GunList yet? Perhaps in there you could kick up a distributor or dealer who's got the model you're looking for?
The model I went for was a 870 20inch with wood stock and normal bead front sight. All their smooth bores come as an ImpCyl choke from what they say on their webpage.