Thanks! Here's some info on it from elsewhere on this forum:
Western Sport Special Group (A91), included Western Sport Special decal, vinyl roof, wood grain instrument panel appliqué, remote control mirror, rim blow steering wheel, sill moulding, belt moulding, front splash pan scoop, cowl moulding, rear Astrotone appliqué, pedals dress-up, bumper guards w/rubber inserts, F78x14 inch white side wall tires, and Rallye wheels. Engine choices were a 225 slant six, 318ci V8, or 383ci V8. This package was released mid-December. 1969 to Los Angeles and San Francisco areas only.
Mine has all the above options, except for one deviation: mine has the Magnum wheels instead of the Rallyes. I checked the fender tag and it's definitely an "A91" coded car. Mine also has factory AC and a split bench. It's basically optioned out like an R/T except for the hardware (all "show" and no "go").
As far as rarety, I found these production numbers on the web:
225 Slant Six = 145
318 2V = 1,066
340 4V = 1
383-2V = 381
So mine's one of the 1066 cars that came with the 318. That makes it somewhat unusual, and in my eyes a little more desirable than a garden-variety base-model, but still not as valuable as a T/A or R/T. I like the fact that it's an uncommon option and an unusual color combo; that's why I want to keep the body & interior mostly stock (although I'm thinking of adding an R/T hood), but bolt-on imnprovements (like the brakes, engine, & trans) are fair game. I honestly don't care much for the latest trend of big wheeled cars, etc., so this one's going to be more of a "resto-rod". Besides, the "Western" decals on the rear fenders are a conversation starter with people who have never heard of it.
I'm leaning toward the 440 myself. I know the big blocks have a different bellhousing bolt pattern, but I found out this car has a 904 auto, so I'd have to put a 727 in there either way. The only real advantage to keeping a small block in it would be that I could reuse the pulleys & brackets from the old motor. The only problem with the 440 is that it's out of a motor home, so I know I'll need to change a lot of parts to make it work.