Mack,
Thanks for the VIN - I decoded it & found your paint is code 702, Smoke Silver, and you have Palomino MB Tex interior (code 174). This is a VERY common combination. I swear half the 87's imported were this combo! I don't like that color much, it's not smoke, it sure ain't silver, why call it "Smoke Silver"? Sheesh. It's gold/champagne to me. My sister has one in that color combo too, and my dad is about to buy one as well - same colors!
Sounds like you got a pretty decent deal, btw! Nice find.
ABS lite is probably just the bulb out in the dash, if it doesn't light when you turn the key on. Try the ABS, it should work - rare failure on these cars, IMO. The headrests often move UP under power, but need help DOWN. If yours won't move up, yeah something hosed. Not a big deal. The tranny should shift positively, and firmly at heavy throttle, but not harsh. That's usually a sign of a vacuum leak somewhere - good luck tracking that down though. If the trans has not been serviced in the last 20kmi, do that ASAP... mine will shift kinda harsh past 20-25kmi, and ususally go back to "normal" with a fluid & filter change. Use Mobil-1 ATF and drain the converter too.
You check the timing chain stretch visually. If the stretch is 3 degrees or less, leave it alone. If it's 4 or more, you probably should replace it, that's the wear limit specified in the factory engine manual. Do that before messing with IP timing, as the timing will change if you replace the chain, and you'll need to do it all over again!
If the chain is OK, then check & adjust the IP timing (buy the IP lock pin tool for ~$30), set to advanced side of spec - 14 ATDC.
There is no casting number for the vac pump. Look at the front cover. If there are 4 Torx head screws in it, like you see in the photo at this URL, it's the new style. If there are NO screws, replace it ASAP:
http://www.meimann.com/images/mercedes/head_gasket/vac_pump1.jpg
Replacing all the climate control pods ain't fun, but sure makes the ACC work better! Here's photos of my dash R&R, and there's a thread on this forum where I posted all the details (let me know if you can't locate it in a search) :
http://www.meimann.com/images/mercedes/W124_dash/
Best regards,