Actually, I'm pretty sure what you need is part # MWC1622. (Part 6 in this diagram) It's a stiff 1/8" thick plate with two captive/welded nuts in it
I'm also pretty sure the ASR2668 is for mounting the anti-burst style latches to side and rear doors (like on ST/half doors, Series doors, etc.)
If you search that correct part number online, it'll give you that one or an alternate superceeded one.
'86 D110 3-door
'97 D90SW - SOLD SEP '14
'94 D90ST - SOLD MAY '13
D90s sold while assigned overseas. You're welcome America!
'06 Range Rover Sport Supercharged
'8X FankenRover D100