Even if child restraint anchor points were not fitted in your market, I would be surprised if the holes for them were not punched in the steel shelf under the carpeted board of the rear shelf. I had the rear carpeted shelf removed from my 190E on the weekend (fitting new speakers). The restraint anchors are simply threaded bushes fitted to a plate which in turn is rivetted to the steel shelf. Markets without the anchors would still have the holes punched into the shelf. You would simply need to make the necessary holes through the carpeted board for after-market restraint anchor bolts which would then mount through the holes in the steel shelf (with appropriate large washer or plate to spread the load). I used this technique when we needed to use child seats in my 350SLC which being a 1973 model had no anchor points fitted.
107.023: 350SLC, 3-speed auto, icon gold, parchment MBtex (sold 2012 after 29 years ownership).
107.026: 500SLC, 4-speed auto, thistle green, green velour.
124.090: 300TE, 4-speed auto, arctic white, cream-beige MBtex.
201.028: 190E 2.3 Sportline, 5-speed manual, arctic white, blue leather.
201.028: 190E 2.3, 4-speed auto, blue-black, grey MBtex.
201.034: 190E 2.3-16, 5-speed manual, blue-black, black leather.