ocabj,
No, you were correct, they have copper jackets. Here's the quote from their website:
"We started our company as BDX Mfg. as a small family operation in 1974. At that time, we did custom reloading. We ran that until 1985 when we sold the reloading portion and went into the bullet manufacturing specialty. We specialized in lead swaged bullets and worked on making a full line of small pistol lead bullets. Things changed and we started manufacturing copper jacketed bullets in 1991. We reorganized and renamed the business Montana Gold Bullet Incorporated. The jacketed bullets have been very popular with past and new customers alike. The CMJ (complete metal jacket) is the newest item in the market from our line. We deal mostly on the wholesale level. We do not have a retail store. We do have pickup orders. Call ahead for packaging, etc.
We want to thank all of our customers for their business."
A couple of years ago I talked to a company that was experimenting with brass plated bullets at the SHOT Show in Las Vegas. They later abandoned the use of brass, since it's more expensive than copper and didn't exhibit any qualities superior to copper for the intended purpose.
Hope this helps.
Fred