In Susan Magoffins journal of her trip west in 1846, she describes the small arsenal in her tent while in new Mexico. She mentions double barrel shotgun, belt pistols, holster pistols and colts new six barreled pistol. I don't believe a walker would have been available yet. Her husband was a wealthy and successful Santa Fe trader and earlier in 1846 they honeymooned and bought supplies for their trip in New York and Philidelphia. Could Sam Magoffin had gotten a colt walker that early?