The relevant passage is found in the Wolf's Dragoons Sourcebook on page 124. Essentially, during Anton Marik's revolt in 3014, both Lieutenant Kerensky and the Bounty Hunter were assigned the same operations area on Nova Roma. The Bounty Hunter's team reported that a certain ravine was clear for Kerensky's heavy lance to move through, and she proceeded into the ravine, wherein her unit was promptly ambushed by a number of Loyalist mechs. With her Marauder heavily-damaged and overheating, she ejected and made her way back to friendly lines...but not before watching the Bounty Hunter's Griffin begin dragging away her own Mech.
The Marauder itself was detailed in RS:3085 Unabridged; Project Phoenix (pg. 189). It downgrades the engine to a 225 and adds 3 jump jets, mounts 14.5 tons of armor, replaces the weapons loadout with 3 PPCs (RA, LA, and RT) and 5 medium lasers (RA, LA, R/L/CT), and mounts 16 Double Heat Sinks. It is unclear whether Natasha piloted this Marauder variant, or if it was retrofitted to this standard via lostech upgrades by the Bounty Hunter. The common wisdom is that this is the variant piloted by Natasha, which gives the BH the reason for colluding with the Loyalists and ambushing Natasha for her Mech (since there's easier ways to acquire a bog-standard Marauder).
There is some speculation that the Warhammer Kerensky piloted hereafter belonged to the Bounty Hunter, but there is no confirmation, and she'd have to work VERY fast to steal it from him, as she appears in a Warhammer in 3015 when she killed Anton Marik after he massacred Dragoon hostages (including Joshua Wolf) on New Delos in an effort to take over command of the Dragoons. Thus I believe rumors of the 'Hammer belonging to the BH to be unfounded.
