I think yours is from 1993 or 1994? Personally I wouldnt be much worried about not much original parts still being there. Original specs for the US Elevation 12,000 weren't very spectacular I recall. The hardtail Elevation 10,000 came with XTR, Ringle, Syncros... , but for some kind of reason the Elev12k only LX or so. Maybe they reasoned downhillers don't need the lightest of the lightest???
If you ever consider to built it period correct again, you can find some inspiration here => Greg Herbold & his bikes
His bikes always look Cool
I think Greg wun the 1993 NORBA DH cup on an Elevation 12,000.
Your Elev12k looks pretty much like my 1994 SkyExpension. Both have a Hardtlite FM1 (steel) rear. My 1995 SkyExpension has an aluminium rear. Other modifications for 1995 were a higher pivot point near the bracket and a modified swing link.
The 1993 and 1994 models were pretty much alike, except for that the taller sizes of the 1993 modelyear had longer headtubes.