Tom,
I'm sorry, I don't know if they ever came w/black pearl. But I do know that almost anything is possible w/Colt. If they were short of white pearl grips and had black on hand from another commemorative, they would use them. Hundreds of standard Colt's were produced in the commemorative production periods with left over parts like blue loading gates on case colored frame guns, NRA Centennial marked barrels, plated ejector rod housings on blue guns, etc. It's well documented in the books about 2nd gen Colts. So different grips won't phase them, I'm sure.
I agree, that Bat Masterson is way over priced! Most of the damage is discolored nickel plating but I can see several spots of corrosion where it's thru the plating which means it has deep pitting in the metal below that. Even a refinish won't get those out. I've seen, we've probably all seen, a gun like this refinished with blued over pits showing and markings polished 1/2 off. The insides are no doubt rusty but not worn out, so should clean-up and work fine. I'd take it for $200 for a project gun! Maybe de-nickel it and leave it in the "white" like an old 1st gen cowboy 6 shooter, rode hard and put away wet. That would look better than trying to make it look new again. Although for $1300 or so Doug Turnbull could do that. He can weld up the bad pits and re-roll marks them.
Jim